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  • ✇MIT News - Nanoscience and nanotechnology | MIT.nano
  • Propelling atomically layered magnets toward green computersMedia Lab
    Globally, computation is booming at an unprecedented rate, fueled by the boons of artificial intelligence. With this, the staggering energy demand of the world’s computing infrastructure has become a major concern, and the development of computing devices that are far more energy-efficient is a leading challenge for the scientific community.  Use of magnetic materials to build computing devices like memories and processors has emerged as a promising avenue for creating “beyond-CMOS” computers,
     

Propelling atomically layered magnets toward green computers

Globally, computation is booming at an unprecedented rate, fueled by the boons of artificial intelligence. With this, the staggering energy demand of the world’s computing infrastructure has become a major concern, and the development of computing devices that are far more energy-efficient is a leading challenge for the scientific community. 

Use of magnetic materials to build computing devices like memories and processors has emerged as a promising avenue for creating “beyond-CMOS” computers, which would use far less energy compared to traditional computers. Magnetization switching in magnets can be used in computation the same way that a transistor switches from open or closed to represent the 0s and 1s of binary code. 

While much of the research along this direction has focused on using bulk magnetic materials, a new class of magnetic materials — called two-dimensional van der Waals magnets — provides superior properties that can improve the scalability and energy efficiency of magnetic devices to make them commercially viable. 

Although the benefits of shifting to 2D magnetic materials are evident, their practical induction into computers has been hindered by some fundamental challenges. Until recently, 2D magnetic materials could operate only at very low temperatures, much like superconductors. So bringing their operating temperatures above room temperature has remained a primary goal. Additionally, for use in computers, it is important that they can be controlled electrically, without the need for magnetic fields. Bridging this fundamental gap, where 2D magnetic materials can be electrically switched above room temperature without any magnetic fields, could potentially catapult the translation of 2D magnets into the next generation of “green” computers.

A team of MIT researchers has now achieved this critical milestone by designing a “van der Waals atomically layered heterostructure” device where a 2D van der Waals magnet, iron gallium telluride, is interfaced with another 2D material, tungsten ditelluride. In an open-access paper published March 15 in Science Advances, the team shows that the magnet can be toggled between the 0 and 1 states simply by applying pulses of electrical current across their two-layer device. 

“Our device enables robust magnetization switching without the need for an external magnetic field, opening up unprecedented opportunities for ultra-low power and environmentally sustainable computing technology for big data and AI,” says lead author Deblina Sarkar, the AT&T Career Development Assistant Professor at the MIT Media Lab and Center for Neurobiological Engineering, and head of the Nano-Cybernetic Biotrek research group. “Moreover, the atomically layered structure of our device provides unique capabilities including improved interface and possibilities of gate voltage tunability, as well as flexible and transparent spintronic technologies.”

Sarkar is joined on the paper by first author Shivam Kajale, a graduate student in Sarkar’s research group at the Media Lab; Thanh Nguyen, a graduate student in the Department of Nuclear Science and Engineering (NSE); Nguyen Tuan Hung, an MIT visiting scholar in NSE and an assistant professor at Tohoku University in Japan; and Mingda Li, associate professor of NSE.

Breaking the mirror symmetries 

When electric current flows through heavy metals like platinum or tantalum, the electrons get segregated in the materials based on their spin component, a phenomenon called the spin Hall effect, says Kajale. The way this segregation happens depends on the material, and particularly its symmetries.

“The conversion of electric current to spin currents in heavy metals lies at the heart of controlling magnets electrically,” Kajale notes. “The microscopic structure of conventionally used materials, like platinum, have a kind of mirror symmetry, which restricts the spin currents only to in-plane spin polarization.”

Kajale explains that two mirror symmetries must be broken to produce an “out-of-plane” spin component that can be transferred to a magnetic layer to induce field-free switching. “Electrical current can 'break' the mirror symmetry along one plane in platinum, but its crystal structure prevents the mirror symmetry from being broken in a second plane.”

In their earlier experiments, the researchers used a small magnetic field to break the second mirror plane. To get rid of the need for a magnetic nudge, Kajale and Sarkar and colleagues looked instead for a material with a structure that could break the second mirror plane without outside help. This led them to another 2D material, tungsten ditelluride. The tungsten ditelluride that the researchers used has an orthorhombic crystal structure. The material itself has one broken mirror plane. Thus, by applying current along its low-symmetry axis (parallel to the broken mirror plane), the resulting spin current has an out-of-plane spin component that can directly induce switching in the ultra-thin magnet interfaced with the tungsten ditelluride. 

“Because it's also a 2D van der Waals material, it can also ensure that when we stack the two materials together, we get pristine interfaces and a good flow of electron spins between the materials,” says Kajale. 

Becoming more energy-efficient 

Computer memory and processors built from magnetic materials use less energy than traditional silicon-based devices. And the van der Waals magnets can offer higher energy efficiency and better scalability compared to bulk magnetic material, the researchers note. 

The electrical current density used for switching the magnet translates to how much energy is dissipated during switching. A lower density means a much more energy-efficient material. “The new design has one of the lowest current densities in van der Waals magnetic materials,” Kajale says. “This new design has an order of magnitude lower in terms of the switching current required in bulk materials. This translates to something like two orders of magnitude improvement in energy efficiency.”

The research team is now looking at similar low-symmetry van der Waals materials to see if they can reduce current density even further. They are also hoping to collaborate with other researchers to find ways to manufacture the 2D magnetic switch devices at commercial scale. 

This work was carried out, in part, using the facilities at MIT.nano. It was funded by the Media Lab, the U.S. National Science Foundation, and the U.S. Department of Energy.

© Image courtesy of the researchers.

The flow of electrical current in the bottom crystalline slab (representing WTe2) breaks a mirror symmetry (shattered glass), while the material itself breaks the other mirror symmetry (cracked glass). The resulting spin current has vertical polarization that switches the magnetic state of the top 2D ferromagnet.

Creative collisions: Crossing the art-science divide

MIT has a rich history of productive collaboration between the arts and the sciences, anchored by the conviction that these two conventionally opposed ways of thinking can form a deeply generative symbiosis that serves to advance and humanize new technologies. 

This ethos was made tangible when the Bauhaus artist and educator György Kepes established the MIT Center for Advanced Visual Studies (CAVS) within the Department of Architecture in 1967. CAVS has since evolved into the Art, Culture, and Technology (ACT) program, which fosters close links to multiple other programs, centers, and labs at MIT. Class 4.373/4.374 (Creating Art, Thinking Science), open to undergraduates and master’s students of all disciplines as well as certain students from the Harvard Graduate School of Design (GSD), is one of the program’s most innovative offerings, proposing a model for how the relationship between art and science might play out at a time of exponential technological growth. 

Now in its third year, the class is supported by an Interdisciplinary Class Development Grant from the MIT Center for Art, Science and Technology (CAST) and draws upon the unparalleled resources of MIT.nano; an artist’s high-tech toolbox for investigating the hidden structures and beauty of our material universe.

High ambitions and critical thinking

The class was initiated by Tobias Putrih, lecturer in ACT, and is taught with the assistance of Ardalan SadeghiKivi MArch ’23, and Aubrie James SM ’24. Central to the success of the class has been the collaboration with co-instructor Vladimir Bulović, the founding director of MIT.nano and Fariborz Maseeh Chair in Emerging Technology, who has positioned the facility as an open-access resource for the campus at large — including MIT’s community of artists. “Creating Art, Thinking Science” unfolds the 100,000 square feet of cleanroom and lab space within the Lisa T. Su Building, inviting participating students to take advantage of cutting-edge equipment for nanoscale visualization and fabrication; in the hands of artists, devices for discovering nanostructures and manipulating atoms become tools for rendering the invisible visible and deconstructing the dynamics of perception itself. 

The expansive goals of the class are tempered by an in-built criticality. “ACT has a unique position as an art program nested within a huge scientific institute — and the challenges of that partnership should not be underestimated,” reflects Putrih. “Science and art are wholly different knowledge systems with distinct historical perspectives. So, how do we communicate? How do we locate that middle ground, that third space?”

An evolving answer, tested and developed throughout the partnership between ACT and MIT.nano, involves a combination of attentive mentorship and sharing of artistic ideas, combined with access to advanced technological resources and hands-on practical training. 

“MIT.nano currently accommodates more than 1,200 individuals to do their work, across 250 different research groups,” says Bulović. “The fact that we count artists among those is a matter of pride for us. We’ve found that the work of our scientists and technologists is enhanced by having access to the language of art as a form of expression — equally, the way that artists express themselves can be stretched beyond what could previously be imagined, simply by having access to the tools and instruments at MIT.nano.”

A playground for experimentation

True to the spirit of the scientific method and artistic iteration, the class is envisioned as a work in progress — a series of propositions and prototypes for how dialogue between scientists and artists might work in practice. The outcomes of those experiments can now be seen installed in the first and second floor galleries at MIT.nano. As part of the facility’s five-year anniversary celebration, the class premiered an exhibition showcasing works created during previous years of “Creating Art, Thinking Science.” 

Visitors to the exhibition, “zero.zerozerozerozerozerozerozerozeroone” (named for the numerical notation for one nanometer), will encounter artworks ranging from a minimalist silicon wafer produced with two-photon polymerization (2PP) technology (“Obscured Invisibility,” 2021, Hyun Woo Park), to traces of an attempt to make vegetable soup in the cleanroom using equipment such as a cryostat, a fluorescing microscope, and a Micro-CT scanner (“May I Please Make You Some Soup?,” 2022, Simone Lasser). 

These works set a precedent for the artworks produced during the fall 2023 iteration of the class. For Ryan Yang, in his senior year studying electrical engineering and computer science at MIT, the chance to engage in open discussion and experimental making has been a rare opportunity to “try something that might not work.” His project explores the possibilities of translating traditional block printing techniques to micron-scale 3D-printing in the MIT.nano labs.

Yang has taken advantage of the arts curriculum at MIT at an early stage in his academic career as an engineer; meanwhile, Ameen Kaleem started out as a filmmaker in New Delhi and is now pursuing a master’s degree in design engineering at Harvard GSD, cross-registered at MIT. 

Kaleem’s project models the process of abiogenesis (the evolution of living organisms from inorganic or inanimate substances) by bringing living moss into the MIT.nano cleanroom facilities to be examined at an atomic scale. “I was interested in the idea that, as a human being in the cleanroom, you are both the most sanitized version of yourself and the dirtiest thing in that space,” she reflects. “Drawing attention to the presence of organic life in the cleanroom is comparable to bringing art into spaces where it might not otherwise exist — a way of humanizing scientific and technological endeavors.”

Consciousness, immersion, and innovation

The students draw upon the legacies of landmark art-science initiatives — including international exhibitions such as “Cybernetic Serendipity” (London ICA, 1968), the “New Tendencies” series (Zagreb, 1961-73), and “Laboratorium” (Antwerp, 1999) — and take inspiration from the instructors’ own creative investigations of the inner workings of different knowledge systems. “In contemporary life, and at MIT in particular, we’re immersed in technology,” says Putrih. “It’s the nature of art to reveal that to us, so that we might see the implications of what we are producing and its potential impact.”

By fostering a mindset of imagination and criticality, combined with building the technical skills to address practical problems, “Creating Art, Thinking Science” seeks to create the conditions for a more expansive version of technological optimism; a culture of innovation in which social and environmental responsibility are seen as productive parameters for enriched creativity. The ripple effects of the class might be years in the making, but as Bulović observes while navigating the exhibition at MIT.nano, “The joy of the collaboration can be felt in the artworks.”

© Photo courtesy of MIT CAST.

Two students engage with an artwork created in 4.373/4.374 (Creating Art, Thinking Science).

Researchers harness 2D magnetic materials for energy-efficient computing

Experimental computer memories and processors built from magnetic materials use far less energy than traditional silicon-based devices. Two-dimensional magnetic materials, composed of layers that are only a few atoms thick, have incredible properties that could allow magnetic-based devices to achieve unprecedented speed, efficiency, and scalability.

While many hurdles must be overcome until these so-called van der Waals magnetic materials can be integrated into functioning computers, MIT researchers took an important step in this direction by demonstrating precise control of a van der Waals magnet at room temperature.

This is key, since magnets composed of atomically thin van der Waals materials can typically only be controlled at extremely cold temperatures, making them difficult to deploy outside a laboratory.

The researchers used pulses of electrical current to switch the direction of the device’s magnetization at room temperature. Magnetic switching can be used in computation, the same way a transistor switches between open and closed to represent 0s and 1s in binary code, or in computer memory, where switching enables data storage.

The team fired bursts of electrons at a magnet made of a new material that can sustain its magnetism at higher temperatures. The experiment leveraged a fundamental property of electrons known as spin, which makes the electrons behave like tiny magnets. By manipulating the spin of electrons that strike the device, the researchers can switch its magnetization.

“The heterostructure device we have developed requires an order of magnitude lower electrical current to switch the van der Waals magnet, compared to that required for bulk magnetic devices,” says Deblina Sarkar, the AT&T Career Development Assistant Professor in the MIT Media Lab and Center for Neurobiological Engineering, head of the Nano-Cybernetic Biotrek Lab, and the senior author of a paper on this technique. “Our device is also more energy efficient than other van der Waals magnets that are unable to switch at room temperature.”

In the future, such a magnet could be used to build faster computers that consume less electricity. It could also enable magnetic computer memories that are nonvolatile, which means they don’t leak information when powered off, or processors that make complex AI algorithms more energy-efficient.

“There is a lot of inertia around trying to improve materials that worked well in the past. But we have shown that if you make radical changes, starting by rethinking the materials you are using, you can potentially get much better solutions,” says Shivam Kajale, a graduate student in Sarkar’s lab and co-lead author of the paper.

Kajale and Sarkar are joined on the paper by co-lead author Thanh Nguyen, a graduate student in the Department of Nuclear Science and Engineering (NSE); Corson Chao, a graduate student in the Department of Materials Science and Engineering (DSME); David Bono, a DSME research scientist; Artittaya Boonkird, an NSE graduate student; and Mingda Li, associate professor of nuclear science and engineering. The research appears this week in Nature Communications.

An atomically thin advantage

Methods to fabricate tiny computer chips in a clean room from bulk materials like silicon can hamper devices. For instance, the layers of material may be barely 1 nanometer thick, so minuscule rough spots on the surface can be severe enough to degrade performance.

By contrast, van der Waals magnetic materials are intrinsically layered and structured in such a way that the surface remains perfectly smooth, even as researchers peel off layers to make thinner devices. In addition, atoms in one layer won’t leak into other layers, enabling the materials to retain their unique properties when stacked in devices.

“In terms of scaling and making these magnetic devices competitive for commercial applications, van der Waals materials are the way to go,” Kajale says.

But there’s a catch. This new class of magnetic materials have typically only been operated at temperatures below 60 kelvins (-351 degrees Fahrenheit). To build a magnetic computer processor or memory, researchers need to use electrical current to operate the magnet at room temperature.

To achieve this, the team focused on an emerging material called iron gallium telluride. This atomically thin material has all the properties needed for effective room temperature magnetism and doesn’t contain rare earth elements, which are undesirable because extracting them is especially destructive to the environment.

Nguyen carefully grew bulk crystals of this 2D material using a special technique. Then, Kajale fabricated a two-layer magnetic device using nanoscale flakes of iron gallium telluride underneath a six-nanometer layer of platinum.

Tiny device in hand, they used an intrinsic property of electrons known as spin to switch its magnetization at room temperature.

Electron ping-pong

While electrons don’t technically “spin” like a top, they do possess the same kind of angular momentum. That spin has a direction, either up or down. The researchers can leverage a property known as spin-orbit coupling to control the spins of electrons they fire at the magnet.

The same way momentum is transferred when one ball hits another, electrons will transfer their “spin momentum” to the 2D magnetic material when they strike it. Depending on the direction of their spins, that momentum transfer can reverse the magnetization.

In a sense, this transfer rotates the magnetization from up to down (or vice-versa), so it is called a “torque,” as in spin-orbit torque switching. Applying a negative electric pulse causes the magnetization to go downward, while a positive pulse causes it to go upward.

The researchers can do this switching at room temperature for two reasons: the special properties of iron gallium telluride and the fact that their technique uses small amounts of electrical current. Pumping too much current into the device would cause it to overheat and demagnetize.

The team faced many challenges over the two years it took to achieve this milestone, Kajale says. Finding the right magnetic material was only half the battle. Since iron gallium telluride oxidizes quickly, fabrication must be done inside a glovebox filled with nitrogen.

“The device is only exposed to air for 10 or 15 seconds, but even after that I have to do a step where I polish it to remove any oxide,” he says.

Now that they have demonstrated room-temperature switching and greater energy efficiency, the researchers plan to keep pushing the performance of magnetic van der Waals materials.

“Our next milestone is to achieve switching without the need for any external magnetic fields. Our aim is to enhance our technology and scale up to bring the versatility of van der Waals magnet to commercial applications,” Sarkar says.

This work was carried out, in part, using the facilities at MIT.Nano and the Harvard University Center for Nanoscale Systems.

© Image: Courtesy of the researchers

This illustration shows electric current being pumped into platinum (the bottom slab), which results in the creation of an electron spin current that switches the magnetic state of the 2D ferromagnet on top. The colored spheres represent the atoms in the 2D material.
  • ✇Latest
  • Kamala Harris' 'Price Gouging' Ban: A New Idea That Has Failed for Thousands of YearsJacob Sullum
    In her first economic policy speech as the 2024 Democratic presidential nominee, Kamala Harris rightly criticized Donald Trump for favoring steep tariffs, saying her Republican opponent "wants to impose what is, in effect, a national sales tax on everyday products and basic necessities that we import from other countries." But in the same speech, Harris pitched a half-baked idea that is just as economically dubious, promising to crack down on "pr
     

Kamala Harris' 'Price Gouging' Ban: A New Idea That Has Failed for Thousands of Years

21. Srpen 2024 v 06:01
Vice President Kamala Harris delivers a speech on her economic platform in Raleigh, North Carolina. | Josh Brown/Zuma Press/Newscom

In her first economic policy speech as the 2024 Democratic presidential nominee, Kamala Harris rightly criticized Donald Trump for favoring steep tariffs, saying her Republican opponent "wants to impose what is, in effect, a national sales tax on everyday products and basic necessities that we import from other countries." But in the same speech, Harris pitched a half-baked idea that is just as economically dubious, promising to crack down on "price gouging" by the grocery industry.

That proposal is so misguided that it provoked undisguised skepticism from mainstream news outlets such as CNN, the Associated Press, The New York Times, and The Washington Post, along with criticism by Democratic economists. It showed that Harris joins Trump in pushing populist prescriptions that would hurt consumers in the name of sticking it to supposed economic villains.

"If your opponent claims you're a 'communist,'" Post columnist Catherine Rampell suggested, "maybe don't start with an economic agenda that can (accurately) be labeled as federal price controls." Harvard economist Jason Furman, who chaired President Barack Obama's Council of Economic Advisers, was equally scathing.

"This is not sensible policy, and I think the biggest hope is that it ends up being a lot of rhetoric and no reality," Furman told the Times. "There's no upside here, and there is some downside."

That downside stems from any attempt to override market signals by dictating prices. High prices allocate goods to consumers who derive the greatest value from them, encourage producers to expand supply, and spur competition that helps bring prices down.

Without those signals, you get hoarding and shortages. This is not some airy-fairy theory; it reflects bitter experience since ancient times with interventions like the one Harris proposes.

Consider what happened when President Richard Nixon imposed wage and price controls in the 1970s. "Ranchers stopped shipping their cattle to the market, farmers drowned their chickens, and consumers emptied the shelves of supermarkets," Daniel Yergin and Joseph Stanislaw note in their 1998 book on the rise of free markets.

Or consider what happened more recently with eggs. Thanks to avian flu, Furman noted, "egg prices went up last year" because "there weren't as many eggs," but the high prices encouraged "more egg production." If federal regulators had tried to suppress egg prices, they would have short-circuited that market response.

Harris, of course, says she would target only unjustified price increases, the kind that amount to "illegal price gouging" by "opportunistic companies." But as she emphasizes, there currently is no such thing under federal law, and any attempt to define it would be plagued by subjectivity and a lack of relevant knowledge.

The fact that Harris pins the sharp grocery price inflation of recent years on corporate greed suggests that her judgment about such matters cannot be trusted. Economists generally rate other factors—including the war in Ukraine as well as pandemic-related supply disruptions, shifts in consumer demand, and stimulus spending—as much more important.

High profits, in any event, are another important signal that encourages investment and competition. By forbidding "excessive profits," Harris' proposed price policing would undermine the motivation they provide.

According to the most recent numbers, the annual inflation rate dropped below 3 percent as of July. With inflation cooling, this might seem like a strange time for Harris to resuscitate an idea that was already proving disastrous thousands of years ago. But as the Times notes, her message "polls well with swing voters."

The broad tariffs that Trump favors, which Harris condemns as "a national sales tax" that would "devastate Americans," also poll well in the abstract. But they are popular only until voters consider the consequences.

In a recent Cato Institute survey, for example, 62 percent of respondents favored a tariff on "imported blue jeans," but that number plummeted when they were asked to imagine the resulting price increases. Harris likewise is counting on voters who like what she says but do not contemplate what it would mean in practice.

© Copyright 2024 by Creators Syndicate Inc.

The post Kamala Harris' 'Price Gouging' Ban: A New Idea That Has Failed for Thousands of Years appeared first on Reason.com.

  • ✇Gnome Stew
  • The Social Contract of PlanningPhil Vecchione
    Planning in RPGs is not a fun activity, so don’t do it. Planning in RPGs is necessary so that we don’t get our characters killed. Both of those statements are true. The optimal way planning should work in your game is somewhere in the middle of those two statements. The optimal way is a combination of genre and play style. And if we were to discuss what that looked like up front, we could define how much planning was necessary for the game we were playing, so that our games had the right amount
     

The Social Contract of Planning

28. Červen 2024 v 12:00

Planning in RPGs is not a fun activity, so don’t do it.
Planning in RPGs is necessary so that we don’t get our characters killed.
Both of those statements are true.

The optimal way planning should work in your game is somewhere in the middle of those two statements. The optimal way is a combination of genre and play style. And if we were to discuss what that looked like up front, we could define how much planning was necessary for the game we were playing, so that our games had the right amount of planning, minimizing the un-fun-ness (take that Bob, our editor), and making it effective enough to keep the characters alive (at least most of them). Let’s talk about how to do that.

Is Planning Un-Fun?

I think so, and I say that as a person whose day job is planning things, and outside of work I plan everything else in my life. In RPGs, planning is just not that fun of an activity. It often consists of the table coming up with ideas and then saying “…but what about this?” going around and around in circles. If you are a player participating in the process, it can be a bit draining, but if you are the GM, waiting for the players to come up with a plan, then you are just sitting there on the outside. It is not how I want to spend my gaming time.

Is Planning Necessary?

Having a plan is a good idea because it aligns the group in terms of their goal and how they are going to achieve it. It allows the group the time to figure out how to best use their resources (equipment, powers, etc). These things greatly increase the group’s chances of being successful and surviving. 

The Components of a Plan

Let’s take a few moments and discuss what makes up a plan. A good plan has all of these, and lesser plans lack detail or are missing some of these parts: 

  • The Goal/Objective – A plan must have an objective. What are we doing? This goal should be shared by the entire group. Are you going in to steal the money? Or are you here to rescue your ex-wife from the Prince? If you are not on the same page about the goal, the group may pursue different goals, split up their resources, or at worse come into conflict.
  • Milestones – The smaller objectives you need to achieve to build up to the goal. It could be disarming the alarm system, or stealing a key from the guard. Some milestones will be in temporal order while others may occur at any time.
  • Information/Intelligence – plans run on information. You can’t plan if you don’t know where you are going, what to expect, how many guards, the terrain around the location, etc. When you lack information you start to make guesses (see below).
  • Risks – Risks are the things you don’t know but think are possible. Risks can be things like a hidden alarm system. Or something like, “What if we can’t take out the guards quietly?” In addition, Risks have a probability (how likely they are to occur) and an impact (how big of a problem it is when they come true). A lot of people who are bad with risks spend too much time worrying about how to handle low probability/high impact risks over high probability/lower impact risks. 
  • Mitigation and Contingencies – Hand in hand with risks are Mitigations (how do we make risk less likely to occur — lower probability) and Contingencies (what do we do if that risk comes true — lower the impact). You can manage neither, one, or both of these. The trick is deciding for each risk what you want to manage. 

This is why Planning is difficult and may not be fun. It is a lot to manage and done well it takes time – time that you are not playing the game. 

The Trust Issue 

The reason that people tend to over-plan is that they fear that there is some piece of information that if the players knew before they put their plan into action, would ensure the success of the goal or prevent excessive harm/death to the characters. To combat this, players do one or both of the following: 

  • Collect as much information/intelligence as possible; at times to excess. 
  • Perform excessive Risk mitigation — naming risks, and coming up with mitigations and contingencies. 

In fact, as a GM, you will know this is happening in the game when these two actions take over the session. When characters feel like they know enough, is when they are ready to switch from planning to action. 

Genre and Playstyle

Before we get to the social contract part of this… we need to discuss two more things. 

Some Genres have plans as one of the tropes. If you are running a game about thieves and heists, or a military game about Spec Ops missions, then those genres require some degree of planning. These games are also best served by mechanics that help compensate for suboptimal planning or help mitigate the lack of planning that occurs at the table. Look at how Blades in the Dark and other Forged in the Dark games remove the need for extensive planning by using mechanics to simulate good planning done by the characters rather than the players.

The other thing is play-style. Some groups get off on playing the cat and mouse game, where the GM comes up with a plan and twists and the players face off to come up with a plan to outsmart the GM. Others want nothing to do with planning. Whatever brings your entire group joy, then there is no wrong-bad-fun, as long as you all, as a group are on the same page.

The Social Contract of Planning

 The truth is that not all RPGs need the same level of planning, but unless you establish that fact, most players will assume they do. 

The truth is that not all RPGs need the same level of planning, but unless you establish that fact, most players will assume they do. 

Some genres do not lean into detailed plans. Superhero games often rely on bold action and powers to overcome problems, not intricate plans. Pulp games also favor action over plans as well. So as you establish your game, consider what the genre and your setting should favor and then combine that with your play style. 

An example: My players had recently finished a Night’s Black Agents campaign. It was a game where planning was key, and the game had some mechanics to support planning. The players knew not to move from planning to action until they had enough intel. They would sometimes spend a session collecting intel and making a plan. Currently, we are playing Mutants in the Now, a game inspired by the Teenage Mutant Ninja Turtles game and comic. In our most recent session, the players were working on a plan for how to attack a Yakuza hotel where some mutant animals were being trafficked. They started to work on a plan worthy of Night’s Black Agents when I reminded them that this game was more action-based. They quickly simplified their plan to “We rappel to the top of the hotel and fight our way to the bottom while rescuing the other mutant animals along the way”. A perfect plan for the setting and genre. 

The key to having players not over-plan is trust between GM and the player. As the GM, I am telling the players that I am not going to punish them for choosing a simple plan. For the players, it is trusting that I am not withholding some key piece of information that would break their simple plan. 

That is not to say you cannot have a twist. The twist is a time-honored trope in all plans. The twist is the unexpected thing that the players have to deal with in the middle of executing the plan which can cause the plan to alter it on the fly. The difference is that what I am promising, as GM, is that the twist will not up-end or thwart the plan. Rather it will be a fun surprise that the characters can deal with.

This is the social contract of planning as a group, for the game you are running (genre and mechanics) and the way you like to play (style). Agree with how much planning is necessary for this game, in general. You can come up with things like this:

  • This game is about a sci-fi Spec Ops team, and the mechanics are gritty, you are going to want to have a good plan before executing an operation. 
  • This game is about mutant animals fighting other mutant animals and criminals, you don’t need more than a simple plan, as most things you encounter are going to be resolved by fighting.

By doing this you are creating expectations for the whole group on how you should handle planning. This is the social contract that you agree to and guides how you play. Establish this in Session Zero and you can set the tone for planning in your campaign, and help keep planning to exactly what it needs to be for your game.

A quick note. Even after you establish a level of planning as part of your game, you can have a story where you change the amount of planning for that session. All you have to do is indicate to the players the change so that they can reset their expectations.. 

Plan Out Your Planning

Planning is not always fun in games, and it can be worse if you are over or under-planning based on the game you are running. But like most things in RPGs, if we do some upfront communication and set some expectations we can dial in planning to just the right amount for the game we are playing. 

This expectation along with any planning mechanics that the game provides can make planning far less tedious while being effective, and make for an overall play experience. 

How do you handle planning in your games? How do you set those expectations with your players? What planning tools do you use or what planning mechanics do you employ?

  • ✇MIT News - Nanoscience and nanotechnology | MIT.nano
  • Propelling atomically layered magnets toward green computersMedia Lab
    Globally, computation is booming at an unprecedented rate, fueled by the boons of artificial intelligence. With this, the staggering energy demand of the world’s computing infrastructure has become a major concern, and the development of computing devices that are far more energy-efficient is a leading challenge for the scientific community.  Use of magnetic materials to build computing devices like memories and processors has emerged as a promising avenue for creating “beyond-CMOS” computers,
     

Propelling atomically layered magnets toward green computers

Globally, computation is booming at an unprecedented rate, fueled by the boons of artificial intelligence. With this, the staggering energy demand of the world’s computing infrastructure has become a major concern, and the development of computing devices that are far more energy-efficient is a leading challenge for the scientific community. 

Use of magnetic materials to build computing devices like memories and processors has emerged as a promising avenue for creating “beyond-CMOS” computers, which would use far less energy compared to traditional computers. Magnetization switching in magnets can be used in computation the same way that a transistor switches from open or closed to represent the 0s and 1s of binary code. 

While much of the research along this direction has focused on using bulk magnetic materials, a new class of magnetic materials — called two-dimensional van der Waals magnets — provides superior properties that can improve the scalability and energy efficiency of magnetic devices to make them commercially viable. 

Although the benefits of shifting to 2D magnetic materials are evident, their practical induction into computers has been hindered by some fundamental challenges. Until recently, 2D magnetic materials could operate only at very low temperatures, much like superconductors. So bringing their operating temperatures above room temperature has remained a primary goal. Additionally, for use in computers, it is important that they can be controlled electrically, without the need for magnetic fields. Bridging this fundamental gap, where 2D magnetic materials can be electrically switched above room temperature without any magnetic fields, could potentially catapult the translation of 2D magnets into the next generation of “green” computers.

A team of MIT researchers has now achieved this critical milestone by designing a “van der Waals atomically layered heterostructure” device where a 2D van der Waals magnet, iron gallium telluride, is interfaced with another 2D material, tungsten ditelluride. In an open-access paper published March 15 in Science Advances, the team shows that the magnet can be toggled between the 0 and 1 states simply by applying pulses of electrical current across their two-layer device. 

“Our device enables robust magnetization switching without the need for an external magnetic field, opening up unprecedented opportunities for ultra-low power and environmentally sustainable computing technology for big data and AI,” says lead author Deblina Sarkar, the AT&T Career Development Assistant Professor at the MIT Media Lab and Center for Neurobiological Engineering, and head of the Nano-Cybernetic Biotrek research group. “Moreover, the atomically layered structure of our device provides unique capabilities including improved interface and possibilities of gate voltage tunability, as well as flexible and transparent spintronic technologies.”

Sarkar is joined on the paper by first author Shivam Kajale, a graduate student in Sarkar’s research group at the Media Lab; Thanh Nguyen, a graduate student in the Department of Nuclear Science and Engineering (NSE); Nguyen Tuan Hung, an MIT visiting scholar in NSE and an assistant professor at Tohoku University in Japan; and Mingda Li, associate professor of NSE.

Breaking the mirror symmetries 

When electric current flows through heavy metals like platinum or tantalum, the electrons get segregated in the materials based on their spin component, a phenomenon called the spin Hall effect, says Kajale. The way this segregation happens depends on the material, and particularly its symmetries.

“The conversion of electric current to spin currents in heavy metals lies at the heart of controlling magnets electrically,” Kajale notes. “The microscopic structure of conventionally used materials, like platinum, have a kind of mirror symmetry, which restricts the spin currents only to in-plane spin polarization.”

Kajale explains that two mirror symmetries must be broken to produce an “out-of-plane” spin component that can be transferred to a magnetic layer to induce field-free switching. “Electrical current can 'break' the mirror symmetry along one plane in platinum, but its crystal structure prevents the mirror symmetry from being broken in a second plane.”

In their earlier experiments, the researchers used a small magnetic field to break the second mirror plane. To get rid of the need for a magnetic nudge, Kajale and Sarkar and colleagues looked instead for a material with a structure that could break the second mirror plane without outside help. This led them to another 2D material, tungsten ditelluride. The tungsten ditelluride that the researchers used has an orthorhombic crystal structure. The material itself has one broken mirror plane. Thus, by applying current along its low-symmetry axis (parallel to the broken mirror plane), the resulting spin current has an out-of-plane spin component that can directly induce switching in the ultra-thin magnet interfaced with the tungsten ditelluride. 

“Because it's also a 2D van der Waals material, it can also ensure that when we stack the two materials together, we get pristine interfaces and a good flow of electron spins between the materials,” says Kajale. 

Becoming more energy-efficient 

Computer memory and processors built from magnetic materials use less energy than traditional silicon-based devices. And the van der Waals magnets can offer higher energy efficiency and better scalability compared to bulk magnetic material, the researchers note. 

The electrical current density used for switching the magnet translates to how much energy is dissipated during switching. A lower density means a much more energy-efficient material. “The new design has one of the lowest current densities in van der Waals magnetic materials,” Kajale says. “This new design has an order of magnitude lower in terms of the switching current required in bulk materials. This translates to something like two orders of magnitude improvement in energy efficiency.”

The research team is now looking at similar low-symmetry van der Waals materials to see if they can reduce current density even further. They are also hoping to collaborate with other researchers to find ways to manufacture the 2D magnetic switch devices at commercial scale. 

This work was carried out, in part, using the facilities at MIT.nano. It was funded by the Media Lab, the U.S. National Science Foundation, and the U.S. Department of Energy.

© Image courtesy of the researchers.

The flow of electrical current in the bottom crystalline slab (representing WTe2) breaks a mirror symmetry (shattered glass), while the material itself breaks the other mirror symmetry (cracked glass). The resulting spin current has vertical polarization that switches the magnetic state of the top 2D ferromagnet.

Creative collisions: Crossing the art-science divide

MIT has a rich history of productive collaboration between the arts and the sciences, anchored by the conviction that these two conventionally opposed ways of thinking can form a deeply generative symbiosis that serves to advance and humanize new technologies. 

This ethos was made tangible when the Bauhaus artist and educator György Kepes established the MIT Center for Advanced Visual Studies (CAVS) within the Department of Architecture in 1967. CAVS has since evolved into the Art, Culture, and Technology (ACT) program, which fosters close links to multiple other programs, centers, and labs at MIT. Class 4.373/4.374 (Creating Art, Thinking Science), open to undergraduates and master’s students of all disciplines as well as certain students from the Harvard Graduate School of Design (GSD), is one of the program’s most innovative offerings, proposing a model for how the relationship between art and science might play out at a time of exponential technological growth. 

Now in its third year, the class is supported by an Interdisciplinary Class Development Grant from the MIT Center for Art, Science and Technology (CAST) and draws upon the unparalleled resources of MIT.nano; an artist’s high-tech toolbox for investigating the hidden structures and beauty of our material universe.

High ambitions and critical thinking

The class was initiated by Tobias Putrih, lecturer in ACT, and is taught with the assistance of Ardalan SadeghiKivi MArch ’23, and Aubrie James SM ’24. Central to the success of the class has been the collaboration with co-instructor Vladimir Bulović, the founding director of MIT.nano and Fariborz Maseeh Chair in Emerging Technology, who has positioned the facility as an open-access resource for the campus at large — including MIT’s community of artists. “Creating Art, Thinking Science” unfolds the 100,000 square feet of cleanroom and lab space within the Lisa T. Su Building, inviting participating students to take advantage of cutting-edge equipment for nanoscale visualization and fabrication; in the hands of artists, devices for discovering nanostructures and manipulating atoms become tools for rendering the invisible visible and deconstructing the dynamics of perception itself. 

The expansive goals of the class are tempered by an in-built criticality. “ACT has a unique position as an art program nested within a huge scientific institute — and the challenges of that partnership should not be underestimated,” reflects Putrih. “Science and art are wholly different knowledge systems with distinct historical perspectives. So, how do we communicate? How do we locate that middle ground, that third space?”

An evolving answer, tested and developed throughout the partnership between ACT and MIT.nano, involves a combination of attentive mentorship and sharing of artistic ideas, combined with access to advanced technological resources and hands-on practical training. 

“MIT.nano currently accommodates more than 1,200 individuals to do their work, across 250 different research groups,” says Bulović. “The fact that we count artists among those is a matter of pride for us. We’ve found that the work of our scientists and technologists is enhanced by having access to the language of art as a form of expression — equally, the way that artists express themselves can be stretched beyond what could previously be imagined, simply by having access to the tools and instruments at MIT.nano.”

A playground for experimentation

True to the spirit of the scientific method and artistic iteration, the class is envisioned as a work in progress — a series of propositions and prototypes for how dialogue between scientists and artists might work in practice. The outcomes of those experiments can now be seen installed in the first and second floor galleries at MIT.nano. As part of the facility’s five-year anniversary celebration, the class premiered an exhibition showcasing works created during previous years of “Creating Art, Thinking Science.” 

Visitors to the exhibition, “zero.zerozerozerozerozerozerozerozeroone” (named for the numerical notation for one nanometer), will encounter artworks ranging from a minimalist silicon wafer produced with two-photon polymerization (2PP) technology (“Obscured Invisibility,” 2021, Hyun Woo Park), to traces of an attempt to make vegetable soup in the cleanroom using equipment such as a cryostat, a fluorescing microscope, and a Micro-CT scanner (“May I Please Make You Some Soup?,” 2022, Simone Lasser). 

These works set a precedent for the artworks produced during the fall 2023 iteration of the class. For Ryan Yang, in his senior year studying electrical engineering and computer science at MIT, the chance to engage in open discussion and experimental making has been a rare opportunity to “try something that might not work.” His project explores the possibilities of translating traditional block printing techniques to micron-scale 3D-printing in the MIT.nano labs.

Yang has taken advantage of the arts curriculum at MIT at an early stage in his academic career as an engineer; meanwhile, Ameen Kaleem started out as a filmmaker in New Delhi and is now pursuing a master’s degree in design engineering at Harvard GSD, cross-registered at MIT. 

Kaleem’s project models the process of abiogenesis (the evolution of living organisms from inorganic or inanimate substances) by bringing living moss into the MIT.nano cleanroom facilities to be examined at an atomic scale. “I was interested in the idea that, as a human being in the cleanroom, you are both the most sanitized version of yourself and the dirtiest thing in that space,” she reflects. “Drawing attention to the presence of organic life in the cleanroom is comparable to bringing art into spaces where it might not otherwise exist — a way of humanizing scientific and technological endeavors.”

Consciousness, immersion, and innovation

The students draw upon the legacies of landmark art-science initiatives — including international exhibitions such as “Cybernetic Serendipity” (London ICA, 1968), the “New Tendencies” series (Zagreb, 1961-73), and “Laboratorium” (Antwerp, 1999) — and take inspiration from the instructors’ own creative investigations of the inner workings of different knowledge systems. “In contemporary life, and at MIT in particular, we’re immersed in technology,” says Putrih. “It’s the nature of art to reveal that to us, so that we might see the implications of what we are producing and its potential impact.”

By fostering a mindset of imagination and criticality, combined with building the technical skills to address practical problems, “Creating Art, Thinking Science” seeks to create the conditions for a more expansive version of technological optimism; a culture of innovation in which social and environmental responsibility are seen as productive parameters for enriched creativity. The ripple effects of the class might be years in the making, but as Bulović observes while navigating the exhibition at MIT.nano, “The joy of the collaboration can be felt in the artworks.”

© Photo courtesy of MIT CAST.

Two students engage with an artwork created in 4.373/4.374 (Creating Art, Thinking Science).

Researchers harness 2D magnetic materials for energy-efficient computing

Experimental computer memories and processors built from magnetic materials use far less energy than traditional silicon-based devices. Two-dimensional magnetic materials, composed of layers that are only a few atoms thick, have incredible properties that could allow magnetic-based devices to achieve unprecedented speed, efficiency, and scalability.

While many hurdles must be overcome until these so-called van der Waals magnetic materials can be integrated into functioning computers, MIT researchers took an important step in this direction by demonstrating precise control of a van der Waals magnet at room temperature.

This is key, since magnets composed of atomically thin van der Waals materials can typically only be controlled at extremely cold temperatures, making them difficult to deploy outside a laboratory.

The researchers used pulses of electrical current to switch the direction of the device’s magnetization at room temperature. Magnetic switching can be used in computation, the same way a transistor switches between open and closed to represent 0s and 1s in binary code, or in computer memory, where switching enables data storage.

The team fired bursts of electrons at a magnet made of a new material that can sustain its magnetism at higher temperatures. The experiment leveraged a fundamental property of electrons known as spin, which makes the electrons behave like tiny magnets. By manipulating the spin of electrons that strike the device, the researchers can switch its magnetization.

“The heterostructure device we have developed requires an order of magnitude lower electrical current to switch the van der Waals magnet, compared to that required for bulk magnetic devices,” says Deblina Sarkar, the AT&T Career Development Assistant Professor in the MIT Media Lab and Center for Neurobiological Engineering, head of the Nano-Cybernetic Biotrek Lab, and the senior author of a paper on this technique. “Our device is also more energy efficient than other van der Waals magnets that are unable to switch at room temperature.”

In the future, such a magnet could be used to build faster computers that consume less electricity. It could also enable magnetic computer memories that are nonvolatile, which means they don’t leak information when powered off, or processors that make complex AI algorithms more energy-efficient.

“There is a lot of inertia around trying to improve materials that worked well in the past. But we have shown that if you make radical changes, starting by rethinking the materials you are using, you can potentially get much better solutions,” says Shivam Kajale, a graduate student in Sarkar’s lab and co-lead author of the paper.

Kajale and Sarkar are joined on the paper by co-lead author Thanh Nguyen, a graduate student in the Department of Nuclear Science and Engineering (NSE); Corson Chao, a graduate student in the Department of Materials Science and Engineering (DSME); David Bono, a DSME research scientist; Artittaya Boonkird, an NSE graduate student; and Mingda Li, associate professor of nuclear science and engineering. The research appears this week in Nature Communications.

An atomically thin advantage

Methods to fabricate tiny computer chips in a clean room from bulk materials like silicon can hamper devices. For instance, the layers of material may be barely 1 nanometer thick, so minuscule rough spots on the surface can be severe enough to degrade performance.

By contrast, van der Waals magnetic materials are intrinsically layered and structured in such a way that the surface remains perfectly smooth, even as researchers peel off layers to make thinner devices. In addition, atoms in one layer won’t leak into other layers, enabling the materials to retain their unique properties when stacked in devices.

“In terms of scaling and making these magnetic devices competitive for commercial applications, van der Waals materials are the way to go,” Kajale says.

But there’s a catch. This new class of magnetic materials have typically only been operated at temperatures below 60 kelvins (-351 degrees Fahrenheit). To build a magnetic computer processor or memory, researchers need to use electrical current to operate the magnet at room temperature.

To achieve this, the team focused on an emerging material called iron gallium telluride. This atomically thin material has all the properties needed for effective room temperature magnetism and doesn’t contain rare earth elements, which are undesirable because extracting them is especially destructive to the environment.

Nguyen carefully grew bulk crystals of this 2D material using a special technique. Then, Kajale fabricated a two-layer magnetic device using nanoscale flakes of iron gallium telluride underneath a six-nanometer layer of platinum.

Tiny device in hand, they used an intrinsic property of electrons known as spin to switch its magnetization at room temperature.

Electron ping-pong

While electrons don’t technically “spin” like a top, they do possess the same kind of angular momentum. That spin has a direction, either up or down. The researchers can leverage a property known as spin-orbit coupling to control the spins of electrons they fire at the magnet.

The same way momentum is transferred when one ball hits another, electrons will transfer their “spin momentum” to the 2D magnetic material when they strike it. Depending on the direction of their spins, that momentum transfer can reverse the magnetization.

In a sense, this transfer rotates the magnetization from up to down (or vice-versa), so it is called a “torque,” as in spin-orbit torque switching. Applying a negative electric pulse causes the magnetization to go downward, while a positive pulse causes it to go upward.

The researchers can do this switching at room temperature for two reasons: the special properties of iron gallium telluride and the fact that their technique uses small amounts of electrical current. Pumping too much current into the device would cause it to overheat and demagnetize.

The team faced many challenges over the two years it took to achieve this milestone, Kajale says. Finding the right magnetic material was only half the battle. Since iron gallium telluride oxidizes quickly, fabrication must be done inside a glovebox filled with nitrogen.

“The device is only exposed to air for 10 or 15 seconds, but even after that I have to do a step where I polish it to remove any oxide,” he says.

Now that they have demonstrated room-temperature switching and greater energy efficiency, the researchers plan to keep pushing the performance of magnetic van der Waals materials.

“Our next milestone is to achieve switching without the need for any external magnetic fields. Our aim is to enhance our technology and scale up to bring the versatility of van der Waals magnet to commercial applications,” Sarkar says.

This work was carried out, in part, using the facilities at MIT.Nano and the Harvard University Center for Nanoscale Systems.

© Image: Courtesy of the researchers

This illustration shows electric current being pumped into platinum (the bottom slab), which results in the creation of an electron spin current that switches the magnetic state of the 2D ferromagnet on top. The colored spheres represent the atoms in the 2D material.
  • ✇MIT News - Nanoscience and nanotechnology | MIT.nano
  • Propelling atomically layered magnets toward green computersMedia Lab
    Globally, computation is booming at an unprecedented rate, fueled by the boons of artificial intelligence. With this, the staggering energy demand of the world’s computing infrastructure has become a major concern, and the development of computing devices that are far more energy-efficient is a leading challenge for the scientific community.  Use of magnetic materials to build computing devices like memories and processors has emerged as a promising avenue for creating “beyond-CMOS” computers,
     

Propelling atomically layered magnets toward green computers

Globally, computation is booming at an unprecedented rate, fueled by the boons of artificial intelligence. With this, the staggering energy demand of the world’s computing infrastructure has become a major concern, and the development of computing devices that are far more energy-efficient is a leading challenge for the scientific community. 

Use of magnetic materials to build computing devices like memories and processors has emerged as a promising avenue for creating “beyond-CMOS” computers, which would use far less energy compared to traditional computers. Magnetization switching in magnets can be used in computation the same way that a transistor switches from open or closed to represent the 0s and 1s of binary code. 

While much of the research along this direction has focused on using bulk magnetic materials, a new class of magnetic materials — called two-dimensional van der Waals magnets — provides superior properties that can improve the scalability and energy efficiency of magnetic devices to make them commercially viable. 

Although the benefits of shifting to 2D magnetic materials are evident, their practical induction into computers has been hindered by some fundamental challenges. Until recently, 2D magnetic materials could operate only at very low temperatures, much like superconductors. So bringing their operating temperatures above room temperature has remained a primary goal. Additionally, for use in computers, it is important that they can be controlled electrically, without the need for magnetic fields. Bridging this fundamental gap, where 2D magnetic materials can be electrically switched above room temperature without any magnetic fields, could potentially catapult the translation of 2D magnets into the next generation of “green” computers.

A team of MIT researchers has now achieved this critical milestone by designing a “van der Waals atomically layered heterostructure” device where a 2D van der Waals magnet, iron gallium telluride, is interfaced with another 2D material, tungsten ditelluride. In an open-access paper published March 15 in Science Advances, the team shows that the magnet can be toggled between the 0 and 1 states simply by applying pulses of electrical current across their two-layer device. 

“Our device enables robust magnetization switching without the need for an external magnetic field, opening up unprecedented opportunities for ultra-low power and environmentally sustainable computing technology for big data and AI,” says lead author Deblina Sarkar, the AT&T Career Development Assistant Professor at the MIT Media Lab and Center for Neurobiological Engineering, and head of the Nano-Cybernetic Biotrek research group. “Moreover, the atomically layered structure of our device provides unique capabilities including improved interface and possibilities of gate voltage tunability, as well as flexible and transparent spintronic technologies.”

Sarkar is joined on the paper by first author Shivam Kajale, a graduate student in Sarkar’s research group at the Media Lab; Thanh Nguyen, a graduate student in the Department of Nuclear Science and Engineering (NSE); Nguyen Tuan Hung, an MIT visiting scholar in NSE and an assistant professor at Tohoku University in Japan; and Mingda Li, associate professor of NSE.

Breaking the mirror symmetries 

When electric current flows through heavy metals like platinum or tantalum, the electrons get segregated in the materials based on their spin component, a phenomenon called the spin Hall effect, says Kajale. The way this segregation happens depends on the material, and particularly its symmetries.

“The conversion of electric current to spin currents in heavy metals lies at the heart of controlling magnets electrically,” Kajale notes. “The microscopic structure of conventionally used materials, like platinum, have a kind of mirror symmetry, which restricts the spin currents only to in-plane spin polarization.”

Kajale explains that two mirror symmetries must be broken to produce an “out-of-plane” spin component that can be transferred to a magnetic layer to induce field-free switching. “Electrical current can 'break' the mirror symmetry along one plane in platinum, but its crystal structure prevents the mirror symmetry from being broken in a second plane.”

In their earlier experiments, the researchers used a small magnetic field to break the second mirror plane. To get rid of the need for a magnetic nudge, Kajale and Sarkar and colleagues looked instead for a material with a structure that could break the second mirror plane without outside help. This led them to another 2D material, tungsten ditelluride. The tungsten ditelluride that the researchers used has an orthorhombic crystal structure. The material itself has one broken mirror plane. Thus, by applying current along its low-symmetry axis (parallel to the broken mirror plane), the resulting spin current has an out-of-plane spin component that can directly induce switching in the ultra-thin magnet interfaced with the tungsten ditelluride. 

“Because it's also a 2D van der Waals material, it can also ensure that when we stack the two materials together, we get pristine interfaces and a good flow of electron spins between the materials,” says Kajale. 

Becoming more energy-efficient 

Computer memory and processors built from magnetic materials use less energy than traditional silicon-based devices. And the van der Waals magnets can offer higher energy efficiency and better scalability compared to bulk magnetic material, the researchers note. 

The electrical current density used for switching the magnet translates to how much energy is dissipated during switching. A lower density means a much more energy-efficient material. “The new design has one of the lowest current densities in van der Waals magnetic materials,” Kajale says. “This new design has an order of magnitude lower in terms of the switching current required in bulk materials. This translates to something like two orders of magnitude improvement in energy efficiency.”

The research team is now looking at similar low-symmetry van der Waals materials to see if they can reduce current density even further. They are also hoping to collaborate with other researchers to find ways to manufacture the 2D magnetic switch devices at commercial scale. 

This work was carried out, in part, using the facilities at MIT.nano. It was funded by the Media Lab, the U.S. National Science Foundation, and the U.S. Department of Energy.

© Image courtesy of the researchers.

The flow of electrical current in the bottom crystalline slab (representing WTe2) breaks a mirror symmetry (shattered glass), while the material itself breaks the other mirror symmetry (cracked glass). The resulting spin current has vertical polarization that switches the magnetic state of the top 2D ferromagnet.

Creative collisions: Crossing the art-science divide

MIT has a rich history of productive collaboration between the arts and the sciences, anchored by the conviction that these two conventionally opposed ways of thinking can form a deeply generative symbiosis that serves to advance and humanize new technologies. 

This ethos was made tangible when the Bauhaus artist and educator György Kepes established the MIT Center for Advanced Visual Studies (CAVS) within the Department of Architecture in 1967. CAVS has since evolved into the Art, Culture, and Technology (ACT) program, which fosters close links to multiple other programs, centers, and labs at MIT. Class 4.373/4.374 (Creating Art, Thinking Science), open to undergraduates and master’s students of all disciplines as well as certain students from the Harvard Graduate School of Design (GSD), is one of the program’s most innovative offerings, proposing a model for how the relationship between art and science might play out at a time of exponential technological growth. 

Now in its third year, the class is supported by an Interdisciplinary Class Development Grant from the MIT Center for Art, Science and Technology (CAST) and draws upon the unparalleled resources of MIT.nano; an artist’s high-tech toolbox for investigating the hidden structures and beauty of our material universe.

High ambitions and critical thinking

The class was initiated by Tobias Putrih, lecturer in ACT, and is taught with the assistance of Ardalan SadeghiKivi MArch ’23, and Aubrie James SM ’24. Central to the success of the class has been the collaboration with co-instructor Vladimir Bulović, the founding director of MIT.nano and Fariborz Maseeh Chair in Emerging Technology, who has positioned the facility as an open-access resource for the campus at large — including MIT’s community of artists. “Creating Art, Thinking Science” unfolds the 100,000 square feet of cleanroom and lab space within the Lisa T. Su Building, inviting participating students to take advantage of cutting-edge equipment for nanoscale visualization and fabrication; in the hands of artists, devices for discovering nanostructures and manipulating atoms become tools for rendering the invisible visible and deconstructing the dynamics of perception itself. 

The expansive goals of the class are tempered by an in-built criticality. “ACT has a unique position as an art program nested within a huge scientific institute — and the challenges of that partnership should not be underestimated,” reflects Putrih. “Science and art are wholly different knowledge systems with distinct historical perspectives. So, how do we communicate? How do we locate that middle ground, that third space?”

An evolving answer, tested and developed throughout the partnership between ACT and MIT.nano, involves a combination of attentive mentorship and sharing of artistic ideas, combined with access to advanced technological resources and hands-on practical training. 

“MIT.nano currently accommodates more than 1,200 individuals to do their work, across 250 different research groups,” says Bulović. “The fact that we count artists among those is a matter of pride for us. We’ve found that the work of our scientists and technologists is enhanced by having access to the language of art as a form of expression — equally, the way that artists express themselves can be stretched beyond what could previously be imagined, simply by having access to the tools and instruments at MIT.nano.”

A playground for experimentation

True to the spirit of the scientific method and artistic iteration, the class is envisioned as a work in progress — a series of propositions and prototypes for how dialogue between scientists and artists might work in practice. The outcomes of those experiments can now be seen installed in the first and second floor galleries at MIT.nano. As part of the facility’s five-year anniversary celebration, the class premiered an exhibition showcasing works created during previous years of “Creating Art, Thinking Science.” 

Visitors to the exhibition, “zero.zerozerozerozerozerozerozerozeroone” (named for the numerical notation for one nanometer), will encounter artworks ranging from a minimalist silicon wafer produced with two-photon polymerization (2PP) technology (“Obscured Invisibility,” 2021, Hyun Woo Park), to traces of an attempt to make vegetable soup in the cleanroom using equipment such as a cryostat, a fluorescing microscope, and a Micro-CT scanner (“May I Please Make You Some Soup?,” 2022, Simone Lasser). 

These works set a precedent for the artworks produced during the fall 2023 iteration of the class. For Ryan Yang, in his senior year studying electrical engineering and computer science at MIT, the chance to engage in open discussion and experimental making has been a rare opportunity to “try something that might not work.” His project explores the possibilities of translating traditional block printing techniques to micron-scale 3D-printing in the MIT.nano labs.

Yang has taken advantage of the arts curriculum at MIT at an early stage in his academic career as an engineer; meanwhile, Ameen Kaleem started out as a filmmaker in New Delhi and is now pursuing a master’s degree in design engineering at Harvard GSD, cross-registered at MIT. 

Kaleem’s project models the process of abiogenesis (the evolution of living organisms from inorganic or inanimate substances) by bringing living moss into the MIT.nano cleanroom facilities to be examined at an atomic scale. “I was interested in the idea that, as a human being in the cleanroom, you are both the most sanitized version of yourself and the dirtiest thing in that space,” she reflects. “Drawing attention to the presence of organic life in the cleanroom is comparable to bringing art into spaces where it might not otherwise exist — a way of humanizing scientific and technological endeavors.”

Consciousness, immersion, and innovation

The students draw upon the legacies of landmark art-science initiatives — including international exhibitions such as “Cybernetic Serendipity” (London ICA, 1968), the “New Tendencies” series (Zagreb, 1961-73), and “Laboratorium” (Antwerp, 1999) — and take inspiration from the instructors’ own creative investigations of the inner workings of different knowledge systems. “In contemporary life, and at MIT in particular, we’re immersed in technology,” says Putrih. “It’s the nature of art to reveal that to us, so that we might see the implications of what we are producing and its potential impact.”

By fostering a mindset of imagination and criticality, combined with building the technical skills to address practical problems, “Creating Art, Thinking Science” seeks to create the conditions for a more expansive version of technological optimism; a culture of innovation in which social and environmental responsibility are seen as productive parameters for enriched creativity. The ripple effects of the class might be years in the making, but as Bulović observes while navigating the exhibition at MIT.nano, “The joy of the collaboration can be felt in the artworks.”

© Photo courtesy of MIT CAST.

Two students engage with an artwork created in 4.373/4.374 (Creating Art, Thinking Science).

Researchers harness 2D magnetic materials for energy-efficient computing

Experimental computer memories and processors built from magnetic materials use far less energy than traditional silicon-based devices. Two-dimensional magnetic materials, composed of layers that are only a few atoms thick, have incredible properties that could allow magnetic-based devices to achieve unprecedented speed, efficiency, and scalability.

While many hurdles must be overcome until these so-called van der Waals magnetic materials can be integrated into functioning computers, MIT researchers took an important step in this direction by demonstrating precise control of a van der Waals magnet at room temperature.

This is key, since magnets composed of atomically thin van der Waals materials can typically only be controlled at extremely cold temperatures, making them difficult to deploy outside a laboratory.

The researchers used pulses of electrical current to switch the direction of the device’s magnetization at room temperature. Magnetic switching can be used in computation, the same way a transistor switches between open and closed to represent 0s and 1s in binary code, or in computer memory, where switching enables data storage.

The team fired bursts of electrons at a magnet made of a new material that can sustain its magnetism at higher temperatures. The experiment leveraged a fundamental property of electrons known as spin, which makes the electrons behave like tiny magnets. By manipulating the spin of electrons that strike the device, the researchers can switch its magnetization.

“The heterostructure device we have developed requires an order of magnitude lower electrical current to switch the van der Waals magnet, compared to that required for bulk magnetic devices,” says Deblina Sarkar, the AT&T Career Development Assistant Professor in the MIT Media Lab and Center for Neurobiological Engineering, head of the Nano-Cybernetic Biotrek Lab, and the senior author of a paper on this technique. “Our device is also more energy efficient than other van der Waals magnets that are unable to switch at room temperature.”

In the future, such a magnet could be used to build faster computers that consume less electricity. It could also enable magnetic computer memories that are nonvolatile, which means they don’t leak information when powered off, or processors that make complex AI algorithms more energy-efficient.

“There is a lot of inertia around trying to improve materials that worked well in the past. But we have shown that if you make radical changes, starting by rethinking the materials you are using, you can potentially get much better solutions,” says Shivam Kajale, a graduate student in Sarkar’s lab and co-lead author of the paper.

Kajale and Sarkar are joined on the paper by co-lead author Thanh Nguyen, a graduate student in the Department of Nuclear Science and Engineering (NSE); Corson Chao, a graduate student in the Department of Materials Science and Engineering (DSME); David Bono, a DSME research scientist; Artittaya Boonkird, an NSE graduate student; and Mingda Li, associate professor of nuclear science and engineering. The research appears this week in Nature Communications.

An atomically thin advantage

Methods to fabricate tiny computer chips in a clean room from bulk materials like silicon can hamper devices. For instance, the layers of material may be barely 1 nanometer thick, so minuscule rough spots on the surface can be severe enough to degrade performance.

By contrast, van der Waals magnetic materials are intrinsically layered and structured in such a way that the surface remains perfectly smooth, even as researchers peel off layers to make thinner devices. In addition, atoms in one layer won’t leak into other layers, enabling the materials to retain their unique properties when stacked in devices.

“In terms of scaling and making these magnetic devices competitive for commercial applications, van der Waals materials are the way to go,” Kajale says.

But there’s a catch. This new class of magnetic materials have typically only been operated at temperatures below 60 kelvins (-351 degrees Fahrenheit). To build a magnetic computer processor or memory, researchers need to use electrical current to operate the magnet at room temperature.

To achieve this, the team focused on an emerging material called iron gallium telluride. This atomically thin material has all the properties needed for effective room temperature magnetism and doesn’t contain rare earth elements, which are undesirable because extracting them is especially destructive to the environment.

Nguyen carefully grew bulk crystals of this 2D material using a special technique. Then, Kajale fabricated a two-layer magnetic device using nanoscale flakes of iron gallium telluride underneath a six-nanometer layer of platinum.

Tiny device in hand, they used an intrinsic property of electrons known as spin to switch its magnetization at room temperature.

Electron ping-pong

While electrons don’t technically “spin” like a top, they do possess the same kind of angular momentum. That spin has a direction, either up or down. The researchers can leverage a property known as spin-orbit coupling to control the spins of electrons they fire at the magnet.

The same way momentum is transferred when one ball hits another, electrons will transfer their “spin momentum” to the 2D magnetic material when they strike it. Depending on the direction of their spins, that momentum transfer can reverse the magnetization.

In a sense, this transfer rotates the magnetization from up to down (or vice-versa), so it is called a “torque,” as in spin-orbit torque switching. Applying a negative electric pulse causes the magnetization to go downward, while a positive pulse causes it to go upward.

The researchers can do this switching at room temperature for two reasons: the special properties of iron gallium telluride and the fact that their technique uses small amounts of electrical current. Pumping too much current into the device would cause it to overheat and demagnetize.

The team faced many challenges over the two years it took to achieve this milestone, Kajale says. Finding the right magnetic material was only half the battle. Since iron gallium telluride oxidizes quickly, fabrication must be done inside a glovebox filled with nitrogen.

“The device is only exposed to air for 10 or 15 seconds, but even after that I have to do a step where I polish it to remove any oxide,” he says.

Now that they have demonstrated room-temperature switching and greater energy efficiency, the researchers plan to keep pushing the performance of magnetic van der Waals materials.

“Our next milestone is to achieve switching without the need for any external magnetic fields. Our aim is to enhance our technology and scale up to bring the versatility of van der Waals magnet to commercial applications,” Sarkar says.

This work was carried out, in part, using the facilities at MIT.Nano and the Harvard University Center for Nanoscale Systems.

© Image: Courtesy of the researchers

This illustration shows electric current being pumped into platinum (the bottom slab), which results in the creation of an electron spin current that switches the magnetic state of the 2D ferromagnet on top. The colored spheres represent the atoms in the 2D material.
  • ✇MIT News - Nanoscience and nanotechnology | MIT.nano
  • Propelling atomically layered magnets toward green computersMedia Lab
    Globally, computation is booming at an unprecedented rate, fueled by the boons of artificial intelligence. With this, the staggering energy demand of the world’s computing infrastructure has become a major concern, and the development of computing devices that are far more energy-efficient is a leading challenge for the scientific community.  Use of magnetic materials to build computing devices like memories and processors has emerged as a promising avenue for creating “beyond-CMOS” computers,
     

Propelling atomically layered magnets toward green computers

Globally, computation is booming at an unprecedented rate, fueled by the boons of artificial intelligence. With this, the staggering energy demand of the world’s computing infrastructure has become a major concern, and the development of computing devices that are far more energy-efficient is a leading challenge for the scientific community. 

Use of magnetic materials to build computing devices like memories and processors has emerged as a promising avenue for creating “beyond-CMOS” computers, which would use far less energy compared to traditional computers. Magnetization switching in magnets can be used in computation the same way that a transistor switches from open or closed to represent the 0s and 1s of binary code. 

While much of the research along this direction has focused on using bulk magnetic materials, a new class of magnetic materials — called two-dimensional van der Waals magnets — provides superior properties that can improve the scalability and energy efficiency of magnetic devices to make them commercially viable. 

Although the benefits of shifting to 2D magnetic materials are evident, their practical induction into computers has been hindered by some fundamental challenges. Until recently, 2D magnetic materials could operate only at very low temperatures, much like superconductors. So bringing their operating temperatures above room temperature has remained a primary goal. Additionally, for use in computers, it is important that they can be controlled electrically, without the need for magnetic fields. Bridging this fundamental gap, where 2D magnetic materials can be electrically switched above room temperature without any magnetic fields, could potentially catapult the translation of 2D magnets into the next generation of “green” computers.

A team of MIT researchers has now achieved this critical milestone by designing a “van der Waals atomically layered heterostructure” device where a 2D van der Waals magnet, iron gallium telluride, is interfaced with another 2D material, tungsten ditelluride. In an open-access paper published March 15 in Science Advances, the team shows that the magnet can be toggled between the 0 and 1 states simply by applying pulses of electrical current across their two-layer device. 

“Our device enables robust magnetization switching without the need for an external magnetic field, opening up unprecedented opportunities for ultra-low power and environmentally sustainable computing technology for big data and AI,” says lead author Deblina Sarkar, the AT&T Career Development Assistant Professor at the MIT Media Lab and Center for Neurobiological Engineering, and head of the Nano-Cybernetic Biotrek research group. “Moreover, the atomically layered structure of our device provides unique capabilities including improved interface and possibilities of gate voltage tunability, as well as flexible and transparent spintronic technologies.”

Sarkar is joined on the paper by first author Shivam Kajale, a graduate student in Sarkar’s research group at the Media Lab; Thanh Nguyen, a graduate student in the Department of Nuclear Science and Engineering (NSE); Nguyen Tuan Hung, an MIT visiting scholar in NSE and an assistant professor at Tohoku University in Japan; and Mingda Li, associate professor of NSE.

Breaking the mirror symmetries 

When electric current flows through heavy metals like platinum or tantalum, the electrons get segregated in the materials based on their spin component, a phenomenon called the spin Hall effect, says Kajale. The way this segregation happens depends on the material, and particularly its symmetries.

“The conversion of electric current to spin currents in heavy metals lies at the heart of controlling magnets electrically,” Kajale notes. “The microscopic structure of conventionally used materials, like platinum, have a kind of mirror symmetry, which restricts the spin currents only to in-plane spin polarization.”

Kajale explains that two mirror symmetries must be broken to produce an “out-of-plane” spin component that can be transferred to a magnetic layer to induce field-free switching. “Electrical current can 'break' the mirror symmetry along one plane in platinum, but its crystal structure prevents the mirror symmetry from being broken in a second plane.”

In their earlier experiments, the researchers used a small magnetic field to break the second mirror plane. To get rid of the need for a magnetic nudge, Kajale and Sarkar and colleagues looked instead for a material with a structure that could break the second mirror plane without outside help. This led them to another 2D material, tungsten ditelluride. The tungsten ditelluride that the researchers used has an orthorhombic crystal structure. The material itself has one broken mirror plane. Thus, by applying current along its low-symmetry axis (parallel to the broken mirror plane), the resulting spin current has an out-of-plane spin component that can directly induce switching in the ultra-thin magnet interfaced with the tungsten ditelluride. 

“Because it's also a 2D van der Waals material, it can also ensure that when we stack the two materials together, we get pristine interfaces and a good flow of electron spins between the materials,” says Kajale. 

Becoming more energy-efficient 

Computer memory and processors built from magnetic materials use less energy than traditional silicon-based devices. And the van der Waals magnets can offer higher energy efficiency and better scalability compared to bulk magnetic material, the researchers note. 

The electrical current density used for switching the magnet translates to how much energy is dissipated during switching. A lower density means a much more energy-efficient material. “The new design has one of the lowest current densities in van der Waals magnetic materials,” Kajale says. “This new design has an order of magnitude lower in terms of the switching current required in bulk materials. This translates to something like two orders of magnitude improvement in energy efficiency.”

The research team is now looking at similar low-symmetry van der Waals materials to see if they can reduce current density even further. They are also hoping to collaborate with other researchers to find ways to manufacture the 2D magnetic switch devices at commercial scale. 

This work was carried out, in part, using the facilities at MIT.nano. It was funded by the Media Lab, the U.S. National Science Foundation, and the U.S. Department of Energy.

© Image courtesy of the researchers.

The flow of electrical current in the bottom crystalline slab (representing WTe2) breaks a mirror symmetry (shattered glass), while the material itself breaks the other mirror symmetry (cracked glass). The resulting spin current has vertical polarization that switches the magnetic state of the top 2D ferromagnet.

Creative collisions: Crossing the art-science divide

MIT has a rich history of productive collaboration between the arts and the sciences, anchored by the conviction that these two conventionally opposed ways of thinking can form a deeply generative symbiosis that serves to advance and humanize new technologies. 

This ethos was made tangible when the Bauhaus artist and educator György Kepes established the MIT Center for Advanced Visual Studies (CAVS) within the Department of Architecture in 1967. CAVS has since evolved into the Art, Culture, and Technology (ACT) program, which fosters close links to multiple other programs, centers, and labs at MIT. Class 4.373/4.374 (Creating Art, Thinking Science), open to undergraduates and master’s students of all disciplines as well as certain students from the Harvard Graduate School of Design (GSD), is one of the program’s most innovative offerings, proposing a model for how the relationship between art and science might play out at a time of exponential technological growth. 

Now in its third year, the class is supported by an Interdisciplinary Class Development Grant from the MIT Center for Art, Science and Technology (CAST) and draws upon the unparalleled resources of MIT.nano; an artist’s high-tech toolbox for investigating the hidden structures and beauty of our material universe.

High ambitions and critical thinking

The class was initiated by Tobias Putrih, lecturer in ACT, and is taught with the assistance of Ardalan SadeghiKivi MArch ’23, and Aubrie James SM ’24. Central to the success of the class has been the collaboration with co-instructor Vladimir Bulović, the founding director of MIT.nano and Fariborz Maseeh Chair in Emerging Technology, who has positioned the facility as an open-access resource for the campus at large — including MIT’s community of artists. “Creating Art, Thinking Science” unfolds the 100,000 square feet of cleanroom and lab space within the Lisa T. Su Building, inviting participating students to take advantage of cutting-edge equipment for nanoscale visualization and fabrication; in the hands of artists, devices for discovering nanostructures and manipulating atoms become tools for rendering the invisible visible and deconstructing the dynamics of perception itself. 

The expansive goals of the class are tempered by an in-built criticality. “ACT has a unique position as an art program nested within a huge scientific institute — and the challenges of that partnership should not be underestimated,” reflects Putrih. “Science and art are wholly different knowledge systems with distinct historical perspectives. So, how do we communicate? How do we locate that middle ground, that third space?”

An evolving answer, tested and developed throughout the partnership between ACT and MIT.nano, involves a combination of attentive mentorship and sharing of artistic ideas, combined with access to advanced technological resources and hands-on practical training. 

“MIT.nano currently accommodates more than 1,200 individuals to do their work, across 250 different research groups,” says Bulović. “The fact that we count artists among those is a matter of pride for us. We’ve found that the work of our scientists and technologists is enhanced by having access to the language of art as a form of expression — equally, the way that artists express themselves can be stretched beyond what could previously be imagined, simply by having access to the tools and instruments at MIT.nano.”

A playground for experimentation

True to the spirit of the scientific method and artistic iteration, the class is envisioned as a work in progress — a series of propositions and prototypes for how dialogue between scientists and artists might work in practice. The outcomes of those experiments can now be seen installed in the first and second floor galleries at MIT.nano. As part of the facility’s five-year anniversary celebration, the class premiered an exhibition showcasing works created during previous years of “Creating Art, Thinking Science.” 

Visitors to the exhibition, “zero.zerozerozerozerozerozerozerozeroone” (named for the numerical notation for one nanometer), will encounter artworks ranging from a minimalist silicon wafer produced with two-photon polymerization (2PP) technology (“Obscured Invisibility,” 2021, Hyun Woo Park), to traces of an attempt to make vegetable soup in the cleanroom using equipment such as a cryostat, a fluorescing microscope, and a Micro-CT scanner (“May I Please Make You Some Soup?,” 2022, Simone Lasser). 

These works set a precedent for the artworks produced during the fall 2023 iteration of the class. For Ryan Yang, in his senior year studying electrical engineering and computer science at MIT, the chance to engage in open discussion and experimental making has been a rare opportunity to “try something that might not work.” His project explores the possibilities of translating traditional block printing techniques to micron-scale 3D-printing in the MIT.nano labs.

Yang has taken advantage of the arts curriculum at MIT at an early stage in his academic career as an engineer; meanwhile, Ameen Kaleem started out as a filmmaker in New Delhi and is now pursuing a master’s degree in design engineering at Harvard GSD, cross-registered at MIT. 

Kaleem’s project models the process of abiogenesis (the evolution of living organisms from inorganic or inanimate substances) by bringing living moss into the MIT.nano cleanroom facilities to be examined at an atomic scale. “I was interested in the idea that, as a human being in the cleanroom, you are both the most sanitized version of yourself and the dirtiest thing in that space,” she reflects. “Drawing attention to the presence of organic life in the cleanroom is comparable to bringing art into spaces where it might not otherwise exist — a way of humanizing scientific and technological endeavors.”

Consciousness, immersion, and innovation

The students draw upon the legacies of landmark art-science initiatives — including international exhibitions such as “Cybernetic Serendipity” (London ICA, 1968), the “New Tendencies” series (Zagreb, 1961-73), and “Laboratorium” (Antwerp, 1999) — and take inspiration from the instructors’ own creative investigations of the inner workings of different knowledge systems. “In contemporary life, and at MIT in particular, we’re immersed in technology,” says Putrih. “It’s the nature of art to reveal that to us, so that we might see the implications of what we are producing and its potential impact.”

By fostering a mindset of imagination and criticality, combined with building the technical skills to address practical problems, “Creating Art, Thinking Science” seeks to create the conditions for a more expansive version of technological optimism; a culture of innovation in which social and environmental responsibility are seen as productive parameters for enriched creativity. The ripple effects of the class might be years in the making, but as Bulović observes while navigating the exhibition at MIT.nano, “The joy of the collaboration can be felt in the artworks.”

© Photo courtesy of MIT CAST.

Two students engage with an artwork created in 4.373/4.374 (Creating Art, Thinking Science).

Researchers harness 2D magnetic materials for energy-efficient computing

Experimental computer memories and processors built from magnetic materials use far less energy than traditional silicon-based devices. Two-dimensional magnetic materials, composed of layers that are only a few atoms thick, have incredible properties that could allow magnetic-based devices to achieve unprecedented speed, efficiency, and scalability.

While many hurdles must be overcome until these so-called van der Waals magnetic materials can be integrated into functioning computers, MIT researchers took an important step in this direction by demonstrating precise control of a van der Waals magnet at room temperature.

This is key, since magnets composed of atomically thin van der Waals materials can typically only be controlled at extremely cold temperatures, making them difficult to deploy outside a laboratory.

The researchers used pulses of electrical current to switch the direction of the device’s magnetization at room temperature. Magnetic switching can be used in computation, the same way a transistor switches between open and closed to represent 0s and 1s in binary code, or in computer memory, where switching enables data storage.

The team fired bursts of electrons at a magnet made of a new material that can sustain its magnetism at higher temperatures. The experiment leveraged a fundamental property of electrons known as spin, which makes the electrons behave like tiny magnets. By manipulating the spin of electrons that strike the device, the researchers can switch its magnetization.

“The heterostructure device we have developed requires an order of magnitude lower electrical current to switch the van der Waals magnet, compared to that required for bulk magnetic devices,” says Deblina Sarkar, the AT&T Career Development Assistant Professor in the MIT Media Lab and Center for Neurobiological Engineering, head of the Nano-Cybernetic Biotrek Lab, and the senior author of a paper on this technique. “Our device is also more energy efficient than other van der Waals magnets that are unable to switch at room temperature.”

In the future, such a magnet could be used to build faster computers that consume less electricity. It could also enable magnetic computer memories that are nonvolatile, which means they don’t leak information when powered off, or processors that make complex AI algorithms more energy-efficient.

“There is a lot of inertia around trying to improve materials that worked well in the past. But we have shown that if you make radical changes, starting by rethinking the materials you are using, you can potentially get much better solutions,” says Shivam Kajale, a graduate student in Sarkar’s lab and co-lead author of the paper.

Kajale and Sarkar are joined on the paper by co-lead author Thanh Nguyen, a graduate student in the Department of Nuclear Science and Engineering (NSE); Corson Chao, a graduate student in the Department of Materials Science and Engineering (DSME); David Bono, a DSME research scientist; Artittaya Boonkird, an NSE graduate student; and Mingda Li, associate professor of nuclear science and engineering. The research appears this week in Nature Communications.

An atomically thin advantage

Methods to fabricate tiny computer chips in a clean room from bulk materials like silicon can hamper devices. For instance, the layers of material may be barely 1 nanometer thick, so minuscule rough spots on the surface can be severe enough to degrade performance.

By contrast, van der Waals magnetic materials are intrinsically layered and structured in such a way that the surface remains perfectly smooth, even as researchers peel off layers to make thinner devices. In addition, atoms in one layer won’t leak into other layers, enabling the materials to retain their unique properties when stacked in devices.

“In terms of scaling and making these magnetic devices competitive for commercial applications, van der Waals materials are the way to go,” Kajale says.

But there’s a catch. This new class of magnetic materials have typically only been operated at temperatures below 60 kelvins (-351 degrees Fahrenheit). To build a magnetic computer processor or memory, researchers need to use electrical current to operate the magnet at room temperature.

To achieve this, the team focused on an emerging material called iron gallium telluride. This atomically thin material has all the properties needed for effective room temperature magnetism and doesn’t contain rare earth elements, which are undesirable because extracting them is especially destructive to the environment.

Nguyen carefully grew bulk crystals of this 2D material using a special technique. Then, Kajale fabricated a two-layer magnetic device using nanoscale flakes of iron gallium telluride underneath a six-nanometer layer of platinum.

Tiny device in hand, they used an intrinsic property of electrons known as spin to switch its magnetization at room temperature.

Electron ping-pong

While electrons don’t technically “spin” like a top, they do possess the same kind of angular momentum. That spin has a direction, either up or down. The researchers can leverage a property known as spin-orbit coupling to control the spins of electrons they fire at the magnet.

The same way momentum is transferred when one ball hits another, electrons will transfer their “spin momentum” to the 2D magnetic material when they strike it. Depending on the direction of their spins, that momentum transfer can reverse the magnetization.

In a sense, this transfer rotates the magnetization from up to down (or vice-versa), so it is called a “torque,” as in spin-orbit torque switching. Applying a negative electric pulse causes the magnetization to go downward, while a positive pulse causes it to go upward.

The researchers can do this switching at room temperature for two reasons: the special properties of iron gallium telluride and the fact that their technique uses small amounts of electrical current. Pumping too much current into the device would cause it to overheat and demagnetize.

The team faced many challenges over the two years it took to achieve this milestone, Kajale says. Finding the right magnetic material was only half the battle. Since iron gallium telluride oxidizes quickly, fabrication must be done inside a glovebox filled with nitrogen.

“The device is only exposed to air for 10 or 15 seconds, but even after that I have to do a step where I polish it to remove any oxide,” he says.

Now that they have demonstrated room-temperature switching and greater energy efficiency, the researchers plan to keep pushing the performance of magnetic van der Waals materials.

“Our next milestone is to achieve switching without the need for any external magnetic fields. Our aim is to enhance our technology and scale up to bring the versatility of van der Waals magnet to commercial applications,” Sarkar says.

This work was carried out, in part, using the facilities at MIT.Nano and the Harvard University Center for Nanoscale Systems.

© Image: Courtesy of the researchers

This illustration shows electric current being pumped into platinum (the bottom slab), which results in the creation of an electron spin current that switches the magnetic state of the 2D ferromagnet on top. The colored spheres represent the atoms in the 2D material.
  • ✇MIT News - Nanoscience and nanotechnology | MIT.nano
  • Propelling atomically layered magnets toward green computersMedia Lab
    Globally, computation is booming at an unprecedented rate, fueled by the boons of artificial intelligence. With this, the staggering energy demand of the world’s computing infrastructure has become a major concern, and the development of computing devices that are far more energy-efficient is a leading challenge for the scientific community.  Use of magnetic materials to build computing devices like memories and processors has emerged as a promising avenue for creating “beyond-CMOS” computers,
     

Propelling atomically layered magnets toward green computers

Globally, computation is booming at an unprecedented rate, fueled by the boons of artificial intelligence. With this, the staggering energy demand of the world’s computing infrastructure has become a major concern, and the development of computing devices that are far more energy-efficient is a leading challenge for the scientific community. 

Use of magnetic materials to build computing devices like memories and processors has emerged as a promising avenue for creating “beyond-CMOS” computers, which would use far less energy compared to traditional computers. Magnetization switching in magnets can be used in computation the same way that a transistor switches from open or closed to represent the 0s and 1s of binary code. 

While much of the research along this direction has focused on using bulk magnetic materials, a new class of magnetic materials — called two-dimensional van der Waals magnets — provides superior properties that can improve the scalability and energy efficiency of magnetic devices to make them commercially viable. 

Although the benefits of shifting to 2D magnetic materials are evident, their practical induction into computers has been hindered by some fundamental challenges. Until recently, 2D magnetic materials could operate only at very low temperatures, much like superconductors. So bringing their operating temperatures above room temperature has remained a primary goal. Additionally, for use in computers, it is important that they can be controlled electrically, without the need for magnetic fields. Bridging this fundamental gap, where 2D magnetic materials can be electrically switched above room temperature without any magnetic fields, could potentially catapult the translation of 2D magnets into the next generation of “green” computers.

A team of MIT researchers has now achieved this critical milestone by designing a “van der Waals atomically layered heterostructure” device where a 2D van der Waals magnet, iron gallium telluride, is interfaced with another 2D material, tungsten ditelluride. In an open-access paper published March 15 in Science Advances, the team shows that the magnet can be toggled between the 0 and 1 states simply by applying pulses of electrical current across their two-layer device. 

“Our device enables robust magnetization switching without the need for an external magnetic field, opening up unprecedented opportunities for ultra-low power and environmentally sustainable computing technology for big data and AI,” says lead author Deblina Sarkar, the AT&T Career Development Assistant Professor at the MIT Media Lab and Center for Neurobiological Engineering, and head of the Nano-Cybernetic Biotrek research group. “Moreover, the atomically layered structure of our device provides unique capabilities including improved interface and possibilities of gate voltage tunability, as well as flexible and transparent spintronic technologies.”

Sarkar is joined on the paper by first author Shivam Kajale, a graduate student in Sarkar’s research group at the Media Lab; Thanh Nguyen, a graduate student in the Department of Nuclear Science and Engineering (NSE); Nguyen Tuan Hung, an MIT visiting scholar in NSE and an assistant professor at Tohoku University in Japan; and Mingda Li, associate professor of NSE.

Breaking the mirror symmetries 

When electric current flows through heavy metals like platinum or tantalum, the electrons get segregated in the materials based on their spin component, a phenomenon called the spin Hall effect, says Kajale. The way this segregation happens depends on the material, and particularly its symmetries.

“The conversion of electric current to spin currents in heavy metals lies at the heart of controlling magnets electrically,” Kajale notes. “The microscopic structure of conventionally used materials, like platinum, have a kind of mirror symmetry, which restricts the spin currents only to in-plane spin polarization.”

Kajale explains that two mirror symmetries must be broken to produce an “out-of-plane” spin component that can be transferred to a magnetic layer to induce field-free switching. “Electrical current can 'break' the mirror symmetry along one plane in platinum, but its crystal structure prevents the mirror symmetry from being broken in a second plane.”

In their earlier experiments, the researchers used a small magnetic field to break the second mirror plane. To get rid of the need for a magnetic nudge, Kajale and Sarkar and colleagues looked instead for a material with a structure that could break the second mirror plane without outside help. This led them to another 2D material, tungsten ditelluride. The tungsten ditelluride that the researchers used has an orthorhombic crystal structure. The material itself has one broken mirror plane. Thus, by applying current along its low-symmetry axis (parallel to the broken mirror plane), the resulting spin current has an out-of-plane spin component that can directly induce switching in the ultra-thin magnet interfaced with the tungsten ditelluride. 

“Because it's also a 2D van der Waals material, it can also ensure that when we stack the two materials together, we get pristine interfaces and a good flow of electron spins between the materials,” says Kajale. 

Becoming more energy-efficient 

Computer memory and processors built from magnetic materials use less energy than traditional silicon-based devices. And the van der Waals magnets can offer higher energy efficiency and better scalability compared to bulk magnetic material, the researchers note. 

The electrical current density used for switching the magnet translates to how much energy is dissipated during switching. A lower density means a much more energy-efficient material. “The new design has one of the lowest current densities in van der Waals magnetic materials,” Kajale says. “This new design has an order of magnitude lower in terms of the switching current required in bulk materials. This translates to something like two orders of magnitude improvement in energy efficiency.”

The research team is now looking at similar low-symmetry van der Waals materials to see if they can reduce current density even further. They are also hoping to collaborate with other researchers to find ways to manufacture the 2D magnetic switch devices at commercial scale. 

This work was carried out, in part, using the facilities at MIT.nano. It was funded by the Media Lab, the U.S. National Science Foundation, and the U.S. Department of Energy.

© Image courtesy of the researchers.

The flow of electrical current in the bottom crystalline slab (representing WTe2) breaks a mirror symmetry (shattered glass), while the material itself breaks the other mirror symmetry (cracked glass). The resulting spin current has vertical polarization that switches the magnetic state of the top 2D ferromagnet.

Creative collisions: Crossing the art-science divide

MIT has a rich history of productive collaboration between the arts and the sciences, anchored by the conviction that these two conventionally opposed ways of thinking can form a deeply generative symbiosis that serves to advance and humanize new technologies. 

This ethos was made tangible when the Bauhaus artist and educator György Kepes established the MIT Center for Advanced Visual Studies (CAVS) within the Department of Architecture in 1967. CAVS has since evolved into the Art, Culture, and Technology (ACT) program, which fosters close links to multiple other programs, centers, and labs at MIT. Class 4.373/4.374 (Creating Art, Thinking Science), open to undergraduates and master’s students of all disciplines as well as certain students from the Harvard Graduate School of Design (GSD), is one of the program’s most innovative offerings, proposing a model for how the relationship between art and science might play out at a time of exponential technological growth. 

Now in its third year, the class is supported by an Interdisciplinary Class Development Grant from the MIT Center for Art, Science and Technology (CAST) and draws upon the unparalleled resources of MIT.nano; an artist’s high-tech toolbox for investigating the hidden structures and beauty of our material universe.

High ambitions and critical thinking

The class was initiated by Tobias Putrih, lecturer in ACT, and is taught with the assistance of Ardalan SadeghiKivi MArch ’23, and Aubrie James SM ’24. Central to the success of the class has been the collaboration with co-instructor Vladimir Bulović, the founding director of MIT.nano and Fariborz Maseeh Chair in Emerging Technology, who has positioned the facility as an open-access resource for the campus at large — including MIT’s community of artists. “Creating Art, Thinking Science” unfolds the 100,000 square feet of cleanroom and lab space within the Lisa T. Su Building, inviting participating students to take advantage of cutting-edge equipment for nanoscale visualization and fabrication; in the hands of artists, devices for discovering nanostructures and manipulating atoms become tools for rendering the invisible visible and deconstructing the dynamics of perception itself. 

The expansive goals of the class are tempered by an in-built criticality. “ACT has a unique position as an art program nested within a huge scientific institute — and the challenges of that partnership should not be underestimated,” reflects Putrih. “Science and art are wholly different knowledge systems with distinct historical perspectives. So, how do we communicate? How do we locate that middle ground, that third space?”

An evolving answer, tested and developed throughout the partnership between ACT and MIT.nano, involves a combination of attentive mentorship and sharing of artistic ideas, combined with access to advanced technological resources and hands-on practical training. 

“MIT.nano currently accommodates more than 1,200 individuals to do their work, across 250 different research groups,” says Bulović. “The fact that we count artists among those is a matter of pride for us. We’ve found that the work of our scientists and technologists is enhanced by having access to the language of art as a form of expression — equally, the way that artists express themselves can be stretched beyond what could previously be imagined, simply by having access to the tools and instruments at MIT.nano.”

A playground for experimentation

True to the spirit of the scientific method and artistic iteration, the class is envisioned as a work in progress — a series of propositions and prototypes for how dialogue between scientists and artists might work in practice. The outcomes of those experiments can now be seen installed in the first and second floor galleries at MIT.nano. As part of the facility’s five-year anniversary celebration, the class premiered an exhibition showcasing works created during previous years of “Creating Art, Thinking Science.” 

Visitors to the exhibition, “zero.zerozerozerozerozerozerozerozeroone” (named for the numerical notation for one nanometer), will encounter artworks ranging from a minimalist silicon wafer produced with two-photon polymerization (2PP) technology (“Obscured Invisibility,” 2021, Hyun Woo Park), to traces of an attempt to make vegetable soup in the cleanroom using equipment such as a cryostat, a fluorescing microscope, and a Micro-CT scanner (“May I Please Make You Some Soup?,” 2022, Simone Lasser). 

These works set a precedent for the artworks produced during the fall 2023 iteration of the class. For Ryan Yang, in his senior year studying electrical engineering and computer science at MIT, the chance to engage in open discussion and experimental making has been a rare opportunity to “try something that might not work.” His project explores the possibilities of translating traditional block printing techniques to micron-scale 3D-printing in the MIT.nano labs.

Yang has taken advantage of the arts curriculum at MIT at an early stage in his academic career as an engineer; meanwhile, Ameen Kaleem started out as a filmmaker in New Delhi and is now pursuing a master’s degree in design engineering at Harvard GSD, cross-registered at MIT. 

Kaleem’s project models the process of abiogenesis (the evolution of living organisms from inorganic or inanimate substances) by bringing living moss into the MIT.nano cleanroom facilities to be examined at an atomic scale. “I was interested in the idea that, as a human being in the cleanroom, you are both the most sanitized version of yourself and the dirtiest thing in that space,” she reflects. “Drawing attention to the presence of organic life in the cleanroom is comparable to bringing art into spaces where it might not otherwise exist — a way of humanizing scientific and technological endeavors.”

Consciousness, immersion, and innovation

The students draw upon the legacies of landmark art-science initiatives — including international exhibitions such as “Cybernetic Serendipity” (London ICA, 1968), the “New Tendencies” series (Zagreb, 1961-73), and “Laboratorium” (Antwerp, 1999) — and take inspiration from the instructors’ own creative investigations of the inner workings of different knowledge systems. “In contemporary life, and at MIT in particular, we’re immersed in technology,” says Putrih. “It’s the nature of art to reveal that to us, so that we might see the implications of what we are producing and its potential impact.”

By fostering a mindset of imagination and criticality, combined with building the technical skills to address practical problems, “Creating Art, Thinking Science” seeks to create the conditions for a more expansive version of technological optimism; a culture of innovation in which social and environmental responsibility are seen as productive parameters for enriched creativity. The ripple effects of the class might be years in the making, but as Bulović observes while navigating the exhibition at MIT.nano, “The joy of the collaboration can be felt in the artworks.”

© Photo courtesy of MIT CAST.

Two students engage with an artwork created in 4.373/4.374 (Creating Art, Thinking Science).

Researchers harness 2D magnetic materials for energy-efficient computing

Experimental computer memories and processors built from magnetic materials use far less energy than traditional silicon-based devices. Two-dimensional magnetic materials, composed of layers that are only a few atoms thick, have incredible properties that could allow magnetic-based devices to achieve unprecedented speed, efficiency, and scalability.

While many hurdles must be overcome until these so-called van der Waals magnetic materials can be integrated into functioning computers, MIT researchers took an important step in this direction by demonstrating precise control of a van der Waals magnet at room temperature.

This is key, since magnets composed of atomically thin van der Waals materials can typically only be controlled at extremely cold temperatures, making them difficult to deploy outside a laboratory.

The researchers used pulses of electrical current to switch the direction of the device’s magnetization at room temperature. Magnetic switching can be used in computation, the same way a transistor switches between open and closed to represent 0s and 1s in binary code, or in computer memory, where switching enables data storage.

The team fired bursts of electrons at a magnet made of a new material that can sustain its magnetism at higher temperatures. The experiment leveraged a fundamental property of electrons known as spin, which makes the electrons behave like tiny magnets. By manipulating the spin of electrons that strike the device, the researchers can switch its magnetization.

“The heterostructure device we have developed requires an order of magnitude lower electrical current to switch the van der Waals magnet, compared to that required for bulk magnetic devices,” says Deblina Sarkar, the AT&T Career Development Assistant Professor in the MIT Media Lab and Center for Neurobiological Engineering, head of the Nano-Cybernetic Biotrek Lab, and the senior author of a paper on this technique. “Our device is also more energy efficient than other van der Waals magnets that are unable to switch at room temperature.”

In the future, such a magnet could be used to build faster computers that consume less electricity. It could also enable magnetic computer memories that are nonvolatile, which means they don’t leak information when powered off, or processors that make complex AI algorithms more energy-efficient.

“There is a lot of inertia around trying to improve materials that worked well in the past. But we have shown that if you make radical changes, starting by rethinking the materials you are using, you can potentially get much better solutions,” says Shivam Kajale, a graduate student in Sarkar’s lab and co-lead author of the paper.

Kajale and Sarkar are joined on the paper by co-lead author Thanh Nguyen, a graduate student in the Department of Nuclear Science and Engineering (NSE); Corson Chao, a graduate student in the Department of Materials Science and Engineering (DSME); David Bono, a DSME research scientist; Artittaya Boonkird, an NSE graduate student; and Mingda Li, associate professor of nuclear science and engineering. The research appears this week in Nature Communications.

An atomically thin advantage

Methods to fabricate tiny computer chips in a clean room from bulk materials like silicon can hamper devices. For instance, the layers of material may be barely 1 nanometer thick, so minuscule rough spots on the surface can be severe enough to degrade performance.

By contrast, van der Waals magnetic materials are intrinsically layered and structured in such a way that the surface remains perfectly smooth, even as researchers peel off layers to make thinner devices. In addition, atoms in one layer won’t leak into other layers, enabling the materials to retain their unique properties when stacked in devices.

“In terms of scaling and making these magnetic devices competitive for commercial applications, van der Waals materials are the way to go,” Kajale says.

But there’s a catch. This new class of magnetic materials have typically only been operated at temperatures below 60 kelvins (-351 degrees Fahrenheit). To build a magnetic computer processor or memory, researchers need to use electrical current to operate the magnet at room temperature.

To achieve this, the team focused on an emerging material called iron gallium telluride. This atomically thin material has all the properties needed for effective room temperature magnetism and doesn’t contain rare earth elements, which are undesirable because extracting them is especially destructive to the environment.

Nguyen carefully grew bulk crystals of this 2D material using a special technique. Then, Kajale fabricated a two-layer magnetic device using nanoscale flakes of iron gallium telluride underneath a six-nanometer layer of platinum.

Tiny device in hand, they used an intrinsic property of electrons known as spin to switch its magnetization at room temperature.

Electron ping-pong

While electrons don’t technically “spin” like a top, they do possess the same kind of angular momentum. That spin has a direction, either up or down. The researchers can leverage a property known as spin-orbit coupling to control the spins of electrons they fire at the magnet.

The same way momentum is transferred when one ball hits another, electrons will transfer their “spin momentum” to the 2D magnetic material when they strike it. Depending on the direction of their spins, that momentum transfer can reverse the magnetization.

In a sense, this transfer rotates the magnetization from up to down (or vice-versa), so it is called a “torque,” as in spin-orbit torque switching. Applying a negative electric pulse causes the magnetization to go downward, while a positive pulse causes it to go upward.

The researchers can do this switching at room temperature for two reasons: the special properties of iron gallium telluride and the fact that their technique uses small amounts of electrical current. Pumping too much current into the device would cause it to overheat and demagnetize.

The team faced many challenges over the two years it took to achieve this milestone, Kajale says. Finding the right magnetic material was only half the battle. Since iron gallium telluride oxidizes quickly, fabrication must be done inside a glovebox filled with nitrogen.

“The device is only exposed to air for 10 or 15 seconds, but even after that I have to do a step where I polish it to remove any oxide,” he says.

Now that they have demonstrated room-temperature switching and greater energy efficiency, the researchers plan to keep pushing the performance of magnetic van der Waals materials.

“Our next milestone is to achieve switching without the need for any external magnetic fields. Our aim is to enhance our technology and scale up to bring the versatility of van der Waals magnet to commercial applications,” Sarkar says.

This work was carried out, in part, using the facilities at MIT.Nano and the Harvard University Center for Nanoscale Systems.

© Image: Courtesy of the researchers

This illustration shows electric current being pumped into platinum (the bottom slab), which results in the creation of an electron spin current that switches the magnetic state of the 2D ferromagnet on top. The colored spheres represent the atoms in the 2D material.
  • ✇IEEE Spectrum
  • Video Friday: 1X Robots Tidy UpEvan Ackerman
    Video Friday is your weekly selection of awesome robotics videos, collected by your friends at IEEE Spectrum robotics. We also post a weekly calendar of upcoming robotics events for the next few months. Please send us your events for inclusion.RoboCup 2024: 17–22 July 2024, EINDHOVEN, NETHERLANDSICRA@40: 23–26 September 2024, ROTTERDAM, NETHERLANDSIROS 2024: 14–18 October 2024, ABU DHABI, UNITED ARAB EMIRATESICSR 2024: 23–26 October 2024, ODENSE, DENMARKCybathlon 2024: 25–27 October 2024, ZURICH
     

Video Friday: 1X Robots Tidy Up

7. Červen 2024 v 18:00


Video Friday is your weekly selection of awesome robotics videos, collected by your friends at IEEE Spectrum robotics. We also post a weekly calendar of upcoming robotics events for the next few months. Please send us your events for inclusion.

RoboCup 2024: 17–22 July 2024, EINDHOVEN, NETHERLANDS
ICRA@40: 23–26 September 2024, ROTTERDAM, NETHERLANDS
IROS 2024: 14–18 October 2024, ABU DHABI, UNITED ARAB EMIRATES
ICSR 2024: 23–26 October 2024, ODENSE, DENMARK
Cybathlon 2024: 25–27 October 2024, ZURICH

Enjoy today’s videos!

In this video, you see the start of 1X’s development of an advanced AI system that chains simple tasks into complex actions using voice commands, allowing seamless multi-robot control and remote operation. By starting with single-task models, we ensure smooth transitions to more powerful unified models, ultimately aiming to automate high-level actions using AI.

This video does not contain teleoperation, computer graphics, cuts, video speedups, or scripted trajectory playback. It’s all controlled via neural networks.

[ 1X ]

As the old adage goes, one cannot claim to be a true man without a visit to the Great Wall of China. XBot-L, a full-sized humanoid robot developed by Robot Era, recently acquitted itself well in a walk along sections of the Great Wall.

[ Robot Era ]

The paper presents a novel rotary wing platform, that is capable of folding and expanding its wings during flight. Our source of inspiration came from birds’ ability to fold their wings to navigate through small spaces and dive. The design of the rotorcraft is based on the monocopter platform, which is inspired by the flight of Samara seeds.

[ AirLab ]

We present a variable stiffness robotic skin (VSRS), a concept that integrates stiffness-changing capabilities, sensing, and actuation into a single, thin modular robot design. Reconfiguring, reconnecting, and reshaping VSRSs allows them to achieve new functions both on and in the absence of a host body.

[ Yale Faboratory ]

Heimdall is a new rover design for the 2024 University Rover Challenge (URC). This video shows highlights of Heimdall’s trip during the four missions at URC 2024.

Heimdall features a split body design with whegs (wheel legs), and a drill for sub-surface sample collection. It also has the ability to manipulate a variety of objects, collect surface samples, and perform onboard spectrometry and chemical tests.

[ WVU ]

I think this may be the first time I’ve seen an autonomous robot using a train? This one is delivering lunch boxes!

[ JSME ]

The AI system used identifies and separates red apples from green apples, after which a robotic arm picks up the red apples identified with a qb SoftHand Industry and gently places them in a basket.

My favorite part is the magnetic apple stem system.

[ QB Robotics ]

DexNex (v0, June 2024) is an anthropomorphic teleoperation testbed for dexterous manipulation at the Center for Robotics and Biosystems at Northwestern University. DexNex recreates human upper-limb functionality through a near 1-to-1 mapping between Operator movements and Avatar actions.

Motion of the Operator’s arms, hands, fingers, and head are fed forward to the Avatar, while fingertip pressures, finger forces, and camera images are fed back to the Operator. DexNex aims to minimize the latency of each subsystem to provide a seamless, immersive, and responsive user experience. Future research includes gaining a better understanding of the criticality of haptic and vision feedback for different manipulation tasks; providing arm-level grounded force feedback; and using machine learning to transfer dexterous skills from the human to the robot.

[ Northwestern ]

Sometimes the best path isn’t the smoothest or straightest surface, it’s the path that’s actually meant to be a path.

[ RaiLab ]

Fulfilling a school requirement by working in a Romanian locomotive factory one week each month, Daniela Rus learned to operate “machines that help us make things.” Appreciation for the practical side of math and science stuck with Daniela, who is now Director of the MIT Computer Science and Artificial Intelligence Laboratory (CSAIL).

[ MIT ]

For AI to achieve its full potential, non-experts need to be let into the development process, says Rumman Chowdhury, CEO and cofounder of Humane Intelligence. She tells the story of farmers fighting for the right to repair their own AI-powered tractors (which some manufacturers actually made illegal), proposing everyone should have the ability to report issues, patch updates or even retrain AI technologies for their specific uses.

[ TED ]

  • ✇MIT News - Nanoscience and nanotechnology | MIT.nano
  • Propelling atomically layered magnets toward green computersMedia Lab
    Globally, computation is booming at an unprecedented rate, fueled by the boons of artificial intelligence. With this, the staggering energy demand of the world’s computing infrastructure has become a major concern, and the development of computing devices that are far more energy-efficient is a leading challenge for the scientific community.  Use of magnetic materials to build computing devices like memories and processors has emerged as a promising avenue for creating “beyond-CMOS” computers,
     

Propelling atomically layered magnets toward green computers

Globally, computation is booming at an unprecedented rate, fueled by the boons of artificial intelligence. With this, the staggering energy demand of the world’s computing infrastructure has become a major concern, and the development of computing devices that are far more energy-efficient is a leading challenge for the scientific community. 

Use of magnetic materials to build computing devices like memories and processors has emerged as a promising avenue for creating “beyond-CMOS” computers, which would use far less energy compared to traditional computers. Magnetization switching in magnets can be used in computation the same way that a transistor switches from open or closed to represent the 0s and 1s of binary code. 

While much of the research along this direction has focused on using bulk magnetic materials, a new class of magnetic materials — called two-dimensional van der Waals magnets — provides superior properties that can improve the scalability and energy efficiency of magnetic devices to make them commercially viable. 

Although the benefits of shifting to 2D magnetic materials are evident, their practical induction into computers has been hindered by some fundamental challenges. Until recently, 2D magnetic materials could operate only at very low temperatures, much like superconductors. So bringing their operating temperatures above room temperature has remained a primary goal. Additionally, for use in computers, it is important that they can be controlled electrically, without the need for magnetic fields. Bridging this fundamental gap, where 2D magnetic materials can be electrically switched above room temperature without any magnetic fields, could potentially catapult the translation of 2D magnets into the next generation of “green” computers.

A team of MIT researchers has now achieved this critical milestone by designing a “van der Waals atomically layered heterostructure” device where a 2D van der Waals magnet, iron gallium telluride, is interfaced with another 2D material, tungsten ditelluride. In an open-access paper published March 15 in Science Advances, the team shows that the magnet can be toggled between the 0 and 1 states simply by applying pulses of electrical current across their two-layer device. 

“Our device enables robust magnetization switching without the need for an external magnetic field, opening up unprecedented opportunities for ultra-low power and environmentally sustainable computing technology for big data and AI,” says lead author Deblina Sarkar, the AT&T Career Development Assistant Professor at the MIT Media Lab and Center for Neurobiological Engineering, and head of the Nano-Cybernetic Biotrek research group. “Moreover, the atomically layered structure of our device provides unique capabilities including improved interface and possibilities of gate voltage tunability, as well as flexible and transparent spintronic technologies.”

Sarkar is joined on the paper by first author Shivam Kajale, a graduate student in Sarkar’s research group at the Media Lab; Thanh Nguyen, a graduate student in the Department of Nuclear Science and Engineering (NSE); Nguyen Tuan Hung, an MIT visiting scholar in NSE and an assistant professor at Tohoku University in Japan; and Mingda Li, associate professor of NSE.

Breaking the mirror symmetries 

When electric current flows through heavy metals like platinum or tantalum, the electrons get segregated in the materials based on their spin component, a phenomenon called the spin Hall effect, says Kajale. The way this segregation happens depends on the material, and particularly its symmetries.

“The conversion of electric current to spin currents in heavy metals lies at the heart of controlling magnets electrically,” Kajale notes. “The microscopic structure of conventionally used materials, like platinum, have a kind of mirror symmetry, which restricts the spin currents only to in-plane spin polarization.”

Kajale explains that two mirror symmetries must be broken to produce an “out-of-plane” spin component that can be transferred to a magnetic layer to induce field-free switching. “Electrical current can 'break' the mirror symmetry along one plane in platinum, but its crystal structure prevents the mirror symmetry from being broken in a second plane.”

In their earlier experiments, the researchers used a small magnetic field to break the second mirror plane. To get rid of the need for a magnetic nudge, Kajale and Sarkar and colleagues looked instead for a material with a structure that could break the second mirror plane without outside help. This led them to another 2D material, tungsten ditelluride. The tungsten ditelluride that the researchers used has an orthorhombic crystal structure. The material itself has one broken mirror plane. Thus, by applying current along its low-symmetry axis (parallel to the broken mirror plane), the resulting spin current has an out-of-plane spin component that can directly induce switching in the ultra-thin magnet interfaced with the tungsten ditelluride. 

“Because it's also a 2D van der Waals material, it can also ensure that when we stack the two materials together, we get pristine interfaces and a good flow of electron spins between the materials,” says Kajale. 

Becoming more energy-efficient 

Computer memory and processors built from magnetic materials use less energy than traditional silicon-based devices. And the van der Waals magnets can offer higher energy efficiency and better scalability compared to bulk magnetic material, the researchers note. 

The electrical current density used for switching the magnet translates to how much energy is dissipated during switching. A lower density means a much more energy-efficient material. “The new design has one of the lowest current densities in van der Waals magnetic materials,” Kajale says. “This new design has an order of magnitude lower in terms of the switching current required in bulk materials. This translates to something like two orders of magnitude improvement in energy efficiency.”

The research team is now looking at similar low-symmetry van der Waals materials to see if they can reduce current density even further. They are also hoping to collaborate with other researchers to find ways to manufacture the 2D magnetic switch devices at commercial scale. 

This work was carried out, in part, using the facilities at MIT.nano. It was funded by the Media Lab, the U.S. National Science Foundation, and the U.S. Department of Energy.

© Image courtesy of the researchers.

The flow of electrical current in the bottom crystalline slab (representing WTe2) breaks a mirror symmetry (shattered glass), while the material itself breaks the other mirror symmetry (cracked glass). The resulting spin current has vertical polarization that switches the magnetic state of the top 2D ferromagnet.

Creative collisions: Crossing the art-science divide

MIT has a rich history of productive collaboration between the arts and the sciences, anchored by the conviction that these two conventionally opposed ways of thinking can form a deeply generative symbiosis that serves to advance and humanize new technologies. 

This ethos was made tangible when the Bauhaus artist and educator György Kepes established the MIT Center for Advanced Visual Studies (CAVS) within the Department of Architecture in 1967. CAVS has since evolved into the Art, Culture, and Technology (ACT) program, which fosters close links to multiple other programs, centers, and labs at MIT. Class 4.373/4.374 (Creating Art, Thinking Science), open to undergraduates and master’s students of all disciplines as well as certain students from the Harvard Graduate School of Design (GSD), is one of the program’s most innovative offerings, proposing a model for how the relationship between art and science might play out at a time of exponential technological growth. 

Now in its third year, the class is supported by an Interdisciplinary Class Development Grant from the MIT Center for Art, Science and Technology (CAST) and draws upon the unparalleled resources of MIT.nano; an artist’s high-tech toolbox for investigating the hidden structures and beauty of our material universe.

High ambitions and critical thinking

The class was initiated by Tobias Putrih, lecturer in ACT, and is taught with the assistance of Ardalan SadeghiKivi MArch ’23, and Aubrie James SM ’24. Central to the success of the class has been the collaboration with co-instructor Vladimir Bulović, the founding director of MIT.nano and Fariborz Maseeh Chair in Emerging Technology, who has positioned the facility as an open-access resource for the campus at large — including MIT’s community of artists. “Creating Art, Thinking Science” unfolds the 100,000 square feet of cleanroom and lab space within the Lisa T. Su Building, inviting participating students to take advantage of cutting-edge equipment for nanoscale visualization and fabrication; in the hands of artists, devices for discovering nanostructures and manipulating atoms become tools for rendering the invisible visible and deconstructing the dynamics of perception itself. 

The expansive goals of the class are tempered by an in-built criticality. “ACT has a unique position as an art program nested within a huge scientific institute — and the challenges of that partnership should not be underestimated,” reflects Putrih. “Science and art are wholly different knowledge systems with distinct historical perspectives. So, how do we communicate? How do we locate that middle ground, that third space?”

An evolving answer, tested and developed throughout the partnership between ACT and MIT.nano, involves a combination of attentive mentorship and sharing of artistic ideas, combined with access to advanced technological resources and hands-on practical training. 

“MIT.nano currently accommodates more than 1,200 individuals to do their work, across 250 different research groups,” says Bulović. “The fact that we count artists among those is a matter of pride for us. We’ve found that the work of our scientists and technologists is enhanced by having access to the language of art as a form of expression — equally, the way that artists express themselves can be stretched beyond what could previously be imagined, simply by having access to the tools and instruments at MIT.nano.”

A playground for experimentation

True to the spirit of the scientific method and artistic iteration, the class is envisioned as a work in progress — a series of propositions and prototypes for how dialogue between scientists and artists might work in practice. The outcomes of those experiments can now be seen installed in the first and second floor galleries at MIT.nano. As part of the facility’s five-year anniversary celebration, the class premiered an exhibition showcasing works created during previous years of “Creating Art, Thinking Science.” 

Visitors to the exhibition, “zero.zerozerozerozerozerozerozerozeroone” (named for the numerical notation for one nanometer), will encounter artworks ranging from a minimalist silicon wafer produced with two-photon polymerization (2PP) technology (“Obscured Invisibility,” 2021, Hyun Woo Park), to traces of an attempt to make vegetable soup in the cleanroom using equipment such as a cryostat, a fluorescing microscope, and a Micro-CT scanner (“May I Please Make You Some Soup?,” 2022, Simone Lasser). 

These works set a precedent for the artworks produced during the fall 2023 iteration of the class. For Ryan Yang, in his senior year studying electrical engineering and computer science at MIT, the chance to engage in open discussion and experimental making has been a rare opportunity to “try something that might not work.” His project explores the possibilities of translating traditional block printing techniques to micron-scale 3D-printing in the MIT.nano labs.

Yang has taken advantage of the arts curriculum at MIT at an early stage in his academic career as an engineer; meanwhile, Ameen Kaleem started out as a filmmaker in New Delhi and is now pursuing a master’s degree in design engineering at Harvard GSD, cross-registered at MIT. 

Kaleem’s project models the process of abiogenesis (the evolution of living organisms from inorganic or inanimate substances) by bringing living moss into the MIT.nano cleanroom facilities to be examined at an atomic scale. “I was interested in the idea that, as a human being in the cleanroom, you are both the most sanitized version of yourself and the dirtiest thing in that space,” she reflects. “Drawing attention to the presence of organic life in the cleanroom is comparable to bringing art into spaces where it might not otherwise exist — a way of humanizing scientific and technological endeavors.”

Consciousness, immersion, and innovation

The students draw upon the legacies of landmark art-science initiatives — including international exhibitions such as “Cybernetic Serendipity” (London ICA, 1968), the “New Tendencies” series (Zagreb, 1961-73), and “Laboratorium” (Antwerp, 1999) — and take inspiration from the instructors’ own creative investigations of the inner workings of different knowledge systems. “In contemporary life, and at MIT in particular, we’re immersed in technology,” says Putrih. “It’s the nature of art to reveal that to us, so that we might see the implications of what we are producing and its potential impact.”

By fostering a mindset of imagination and criticality, combined with building the technical skills to address practical problems, “Creating Art, Thinking Science” seeks to create the conditions for a more expansive version of technological optimism; a culture of innovation in which social and environmental responsibility are seen as productive parameters for enriched creativity. The ripple effects of the class might be years in the making, but as Bulović observes while navigating the exhibition at MIT.nano, “The joy of the collaboration can be felt in the artworks.”

© Photo courtesy of MIT CAST.

Two students engage with an artwork created in 4.373/4.374 (Creating Art, Thinking Science).

Researchers harness 2D magnetic materials for energy-efficient computing

Experimental computer memories and processors built from magnetic materials use far less energy than traditional silicon-based devices. Two-dimensional magnetic materials, composed of layers that are only a few atoms thick, have incredible properties that could allow magnetic-based devices to achieve unprecedented speed, efficiency, and scalability.

While many hurdles must be overcome until these so-called van der Waals magnetic materials can be integrated into functioning computers, MIT researchers took an important step in this direction by demonstrating precise control of a van der Waals magnet at room temperature.

This is key, since magnets composed of atomically thin van der Waals materials can typically only be controlled at extremely cold temperatures, making them difficult to deploy outside a laboratory.

The researchers used pulses of electrical current to switch the direction of the device’s magnetization at room temperature. Magnetic switching can be used in computation, the same way a transistor switches between open and closed to represent 0s and 1s in binary code, or in computer memory, where switching enables data storage.

The team fired bursts of electrons at a magnet made of a new material that can sustain its magnetism at higher temperatures. The experiment leveraged a fundamental property of electrons known as spin, which makes the electrons behave like tiny magnets. By manipulating the spin of electrons that strike the device, the researchers can switch its magnetization.

“The heterostructure device we have developed requires an order of magnitude lower electrical current to switch the van der Waals magnet, compared to that required for bulk magnetic devices,” says Deblina Sarkar, the AT&T Career Development Assistant Professor in the MIT Media Lab and Center for Neurobiological Engineering, head of the Nano-Cybernetic Biotrek Lab, and the senior author of a paper on this technique. “Our device is also more energy efficient than other van der Waals magnets that are unable to switch at room temperature.”

In the future, such a magnet could be used to build faster computers that consume less electricity. It could also enable magnetic computer memories that are nonvolatile, which means they don’t leak information when powered off, or processors that make complex AI algorithms more energy-efficient.

“There is a lot of inertia around trying to improve materials that worked well in the past. But we have shown that if you make radical changes, starting by rethinking the materials you are using, you can potentially get much better solutions,” says Shivam Kajale, a graduate student in Sarkar’s lab and co-lead author of the paper.

Kajale and Sarkar are joined on the paper by co-lead author Thanh Nguyen, a graduate student in the Department of Nuclear Science and Engineering (NSE); Corson Chao, a graduate student in the Department of Materials Science and Engineering (DSME); David Bono, a DSME research scientist; Artittaya Boonkird, an NSE graduate student; and Mingda Li, associate professor of nuclear science and engineering. The research appears this week in Nature Communications.

An atomically thin advantage

Methods to fabricate tiny computer chips in a clean room from bulk materials like silicon can hamper devices. For instance, the layers of material may be barely 1 nanometer thick, so minuscule rough spots on the surface can be severe enough to degrade performance.

By contrast, van der Waals magnetic materials are intrinsically layered and structured in such a way that the surface remains perfectly smooth, even as researchers peel off layers to make thinner devices. In addition, atoms in one layer won’t leak into other layers, enabling the materials to retain their unique properties when stacked in devices.

“In terms of scaling and making these magnetic devices competitive for commercial applications, van der Waals materials are the way to go,” Kajale says.

But there’s a catch. This new class of magnetic materials have typically only been operated at temperatures below 60 kelvins (-351 degrees Fahrenheit). To build a magnetic computer processor or memory, researchers need to use electrical current to operate the magnet at room temperature.

To achieve this, the team focused on an emerging material called iron gallium telluride. This atomically thin material has all the properties needed for effective room temperature magnetism and doesn’t contain rare earth elements, which are undesirable because extracting them is especially destructive to the environment.

Nguyen carefully grew bulk crystals of this 2D material using a special technique. Then, Kajale fabricated a two-layer magnetic device using nanoscale flakes of iron gallium telluride underneath a six-nanometer layer of platinum.

Tiny device in hand, they used an intrinsic property of electrons known as spin to switch its magnetization at room temperature.

Electron ping-pong

While electrons don’t technically “spin” like a top, they do possess the same kind of angular momentum. That spin has a direction, either up or down. The researchers can leverage a property known as spin-orbit coupling to control the spins of electrons they fire at the magnet.

The same way momentum is transferred when one ball hits another, electrons will transfer their “spin momentum” to the 2D magnetic material when they strike it. Depending on the direction of their spins, that momentum transfer can reverse the magnetization.

In a sense, this transfer rotates the magnetization from up to down (or vice-versa), so it is called a “torque,” as in spin-orbit torque switching. Applying a negative electric pulse causes the magnetization to go downward, while a positive pulse causes it to go upward.

The researchers can do this switching at room temperature for two reasons: the special properties of iron gallium telluride and the fact that their technique uses small amounts of electrical current. Pumping too much current into the device would cause it to overheat and demagnetize.

The team faced many challenges over the two years it took to achieve this milestone, Kajale says. Finding the right magnetic material was only half the battle. Since iron gallium telluride oxidizes quickly, fabrication must be done inside a glovebox filled with nitrogen.

“The device is only exposed to air for 10 or 15 seconds, but even after that I have to do a step where I polish it to remove any oxide,” he says.

Now that they have demonstrated room-temperature switching and greater energy efficiency, the researchers plan to keep pushing the performance of magnetic van der Waals materials.

“Our next milestone is to achieve switching without the need for any external magnetic fields. Our aim is to enhance our technology and scale up to bring the versatility of van der Waals magnet to commercial applications,” Sarkar says.

This work was carried out, in part, using the facilities at MIT.Nano and the Harvard University Center for Nanoscale Systems.

© Image: Courtesy of the researchers

This illustration shows electric current being pumped into platinum (the bottom slab), which results in the creation of an electron spin current that switches the magnetic state of the 2D ferromagnet on top. The colored spheres represent the atoms in the 2D material.
  • ✇Ask a Game Dev
  • How often do game developers miss deadlines/milestones due to unexpected things?
    For developers in the trenches like me or my team, it's a fairly common occurrence that individual contributors will not be able to finish certain tasks by a given deadline. Sometimes the estimates and the actual work needed are nowhere near congruent, sometimes there are dependencies that took longer to work out than expected, sometimes there are unpredictable events like system outages or developers needing to take a medical leave of absence. In such situations, we adjust what we're delivering
     

How often do game developers miss deadlines/milestones due to unexpected things?

23. Květen 2024 v 18:02

For developers in the trenches like me or my team, it's a fairly common occurrence that individual contributors will not be able to finish certain tasks by a given deadline. Sometimes the estimates and the actual work needed are nowhere near congruent, sometimes there are dependencies that took longer to work out than expected, sometimes there are unpredictable events like system outages or developers needing to take a medical leave of absence. In such situations, we adjust what we're delivering for this milestone and that task and any of its dependencies usually gets "punted" to the next milestone. Individual tasks can often shift back and forth without affecting the overall milestone too much.

It is actually possible for an entire milestone to slip as well - if the mission-critical deliverables for the milestone aren't done in time for whatever reason, the milestone isn't going to be accepted by the money people. Remember, the milestone schedule is originally pitched by the studio and agreed to by the publisher. It outlines exactly what the studio needs to deliver and demonstrate at each milestone and when each milestone should be there. Independent developer studios are often paid by the milestone, so missing or delaying a milestone delivery can mean that we don't get paid until we deliver.

When studios start missing milestones, the publisher often steps in to "meddle". Missing an entire milestone by a significant time frame is a big deal and often means the entire delivery schedule needs to be re-negotiated and re-planned. It's a sign of development hell and a project in a lot of trouble. From the publisher perspective, this is saving the project - things are already off the rails and need fixing or the entire project will need to be cancelled and the studio cut loose.

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Got a burning question you want answered?

Anxious about possibly hitting bugs i can't solve and having to cancel my games

I've been doing game Dev for 5 months now and I've started small at the start with following Pong and Flappy bird tutorials and other simple arcade games, and when i feel like I've reached a ceiling with the complexity level i move on to something more complex (Asteroids clone, simple twin stick shooter ,etc...) and when I'm done with a tutorial, i like to add my own things to them, as in adding entire new features to them or new levels or sort of "remixing" them into something new and maybe adding new original graphics

I make sure to never bite off more than i could chew with projects, so i wouldn't have to inevitability cancel them, i always divide the entire project into parts inside my head, these parts are the main features of the game(movement, tile-maps, combat) , and then i divide each feature into lines of code/functions that i can write in Godot

and with each line of code i think "do i have enough coding knowledge and experience to implement this feature in the game without hitting a big roadblock and having to cancel the game ?"and if i feel like i can do it, then i just start with the project

but last night i got kinda stressed because i thought that i might have to possibly cancel a project that i really cared about

it's a really small 5 minute prototype for a Metroidvania, I'm writing most of the code and getting the assets from a nice tutorial series, so yeah everything was going smoothly until i encountered a tricky bug that made the player jump too high, which would break the game since the player would reach places they weren't meant to reach yet, i posted the bug on this forum and other sites and i got a response within 5 minutes that resolved my issue with 1 simple line of code

but while i was typing the post and trying to solve the bug on my own i honestly felt pretty worried, it's because the movement code for my player character is relatively complex and i wasn't sure where the bug is exactly so i posted the 100 or so lines of code that were related to movement, i was thinking stuff like "what if nobody answers my question because nobody's gonna read 100 lines of code?" "what if I had made a mistake and bit off more than i could chew despite all my careful planning and scoping?" "what if I'm gonna have to cancel it ?" "maybe i shouldn't have gotten attached to this project..."

I feel kinda stressed now because I'm worried about encountering these scenarios

I feel like maybe I'm overthinking this and i just shouldn't hype up projects too much in my head + not worry too much since the bug could literally be solved in 5 minutes

and yeah I tend to always worry about these sorts of things 🤡

  • ✇MIT News - Nanoscience and nanotechnology | MIT.nano
  • Propelling atomically layered magnets toward green computersMedia Lab
    Globally, computation is booming at an unprecedented rate, fueled by the boons of artificial intelligence. With this, the staggering energy demand of the world’s computing infrastructure has become a major concern, and the development of computing devices that are far more energy-efficient is a leading challenge for the scientific community.  Use of magnetic materials to build computing devices like memories and processors has emerged as a promising avenue for creating “beyond-CMOS” computers,
     

Propelling atomically layered magnets toward green computers

Globally, computation is booming at an unprecedented rate, fueled by the boons of artificial intelligence. With this, the staggering energy demand of the world’s computing infrastructure has become a major concern, and the development of computing devices that are far more energy-efficient is a leading challenge for the scientific community. 

Use of magnetic materials to build computing devices like memories and processors has emerged as a promising avenue for creating “beyond-CMOS” computers, which would use far less energy compared to traditional computers. Magnetization switching in magnets can be used in computation the same way that a transistor switches from open or closed to represent the 0s and 1s of binary code. 

While much of the research along this direction has focused on using bulk magnetic materials, a new class of magnetic materials — called two-dimensional van der Waals magnets — provides superior properties that can improve the scalability and energy efficiency of magnetic devices to make them commercially viable. 

Although the benefits of shifting to 2D magnetic materials are evident, their practical induction into computers has been hindered by some fundamental challenges. Until recently, 2D magnetic materials could operate only at very low temperatures, much like superconductors. So bringing their operating temperatures above room temperature has remained a primary goal. Additionally, for use in computers, it is important that they can be controlled electrically, without the need for magnetic fields. Bridging this fundamental gap, where 2D magnetic materials can be electrically switched above room temperature without any magnetic fields, could potentially catapult the translation of 2D magnets into the next generation of “green” computers.

A team of MIT researchers has now achieved this critical milestone by designing a “van der Waals atomically layered heterostructure” device where a 2D van der Waals magnet, iron gallium telluride, is interfaced with another 2D material, tungsten ditelluride. In an open-access paper published March 15 in Science Advances, the team shows that the magnet can be toggled between the 0 and 1 states simply by applying pulses of electrical current across their two-layer device. 

“Our device enables robust magnetization switching without the need for an external magnetic field, opening up unprecedented opportunities for ultra-low power and environmentally sustainable computing technology for big data and AI,” says lead author Deblina Sarkar, the AT&T Career Development Assistant Professor at the MIT Media Lab and Center for Neurobiological Engineering, and head of the Nano-Cybernetic Biotrek research group. “Moreover, the atomically layered structure of our device provides unique capabilities including improved interface and possibilities of gate voltage tunability, as well as flexible and transparent spintronic technologies.”

Sarkar is joined on the paper by first author Shivam Kajale, a graduate student in Sarkar’s research group at the Media Lab; Thanh Nguyen, a graduate student in the Department of Nuclear Science and Engineering (NSE); Nguyen Tuan Hung, an MIT visiting scholar in NSE and an assistant professor at Tohoku University in Japan; and Mingda Li, associate professor of NSE.

Breaking the mirror symmetries 

When electric current flows through heavy metals like platinum or tantalum, the electrons get segregated in the materials based on their spin component, a phenomenon called the spin Hall effect, says Kajale. The way this segregation happens depends on the material, and particularly its symmetries.

“The conversion of electric current to spin currents in heavy metals lies at the heart of controlling magnets electrically,” Kajale notes. “The microscopic structure of conventionally used materials, like platinum, have a kind of mirror symmetry, which restricts the spin currents only to in-plane spin polarization.”

Kajale explains that two mirror symmetries must be broken to produce an “out-of-plane” spin component that can be transferred to a magnetic layer to induce field-free switching. “Electrical current can 'break' the mirror symmetry along one plane in platinum, but its crystal structure prevents the mirror symmetry from being broken in a second plane.”

In their earlier experiments, the researchers used a small magnetic field to break the second mirror plane. To get rid of the need for a magnetic nudge, Kajale and Sarkar and colleagues looked instead for a material with a structure that could break the second mirror plane without outside help. This led them to another 2D material, tungsten ditelluride. The tungsten ditelluride that the researchers used has an orthorhombic crystal structure. The material itself has one broken mirror plane. Thus, by applying current along its low-symmetry axis (parallel to the broken mirror plane), the resulting spin current has an out-of-plane spin component that can directly induce switching in the ultra-thin magnet interfaced with the tungsten ditelluride. 

“Because it's also a 2D van der Waals material, it can also ensure that when we stack the two materials together, we get pristine interfaces and a good flow of electron spins between the materials,” says Kajale. 

Becoming more energy-efficient 

Computer memory and processors built from magnetic materials use less energy than traditional silicon-based devices. And the van der Waals magnets can offer higher energy efficiency and better scalability compared to bulk magnetic material, the researchers note. 

The electrical current density used for switching the magnet translates to how much energy is dissipated during switching. A lower density means a much more energy-efficient material. “The new design has one of the lowest current densities in van der Waals magnetic materials,” Kajale says. “This new design has an order of magnitude lower in terms of the switching current required in bulk materials. This translates to something like two orders of magnitude improvement in energy efficiency.”

The research team is now looking at similar low-symmetry van der Waals materials to see if they can reduce current density even further. They are also hoping to collaborate with other researchers to find ways to manufacture the 2D magnetic switch devices at commercial scale. 

This work was carried out, in part, using the facilities at MIT.nano. It was funded by the Media Lab, the U.S. National Science Foundation, and the U.S. Department of Energy.

© Image courtesy of the researchers.

The flow of electrical current in the bottom crystalline slab (representing WTe2) breaks a mirror symmetry (shattered glass), while the material itself breaks the other mirror symmetry (cracked glass). The resulting spin current has vertical polarization that switches the magnetic state of the top 2D ferromagnet.

Creative collisions: Crossing the art-science divide

MIT has a rich history of productive collaboration between the arts and the sciences, anchored by the conviction that these two conventionally opposed ways of thinking can form a deeply generative symbiosis that serves to advance and humanize new technologies. 

This ethos was made tangible when the Bauhaus artist and educator György Kepes established the MIT Center for Advanced Visual Studies (CAVS) within the Department of Architecture in 1967. CAVS has since evolved into the Art, Culture, and Technology (ACT) program, which fosters close links to multiple other programs, centers, and labs at MIT. Class 4.373/4.374 (Creating Art, Thinking Science), open to undergraduates and master’s students of all disciplines as well as certain students from the Harvard Graduate School of Design (GSD), is one of the program’s most innovative offerings, proposing a model for how the relationship between art and science might play out at a time of exponential technological growth. 

Now in its third year, the class is supported by an Interdisciplinary Class Development Grant from the MIT Center for Art, Science and Technology (CAST) and draws upon the unparalleled resources of MIT.nano; an artist’s high-tech toolbox for investigating the hidden structures and beauty of our material universe.

High ambitions and critical thinking

The class was initiated by Tobias Putrih, lecturer in ACT, and is taught with the assistance of Ardalan SadeghiKivi MArch ’23, and Aubrie James SM ’24. Central to the success of the class has been the collaboration with co-instructor Vladimir Bulović, the founding director of MIT.nano and Fariborz Maseeh Chair in Emerging Technology, who has positioned the facility as an open-access resource for the campus at large — including MIT’s community of artists. “Creating Art, Thinking Science” unfolds the 100,000 square feet of cleanroom and lab space within the Lisa T. Su Building, inviting participating students to take advantage of cutting-edge equipment for nanoscale visualization and fabrication; in the hands of artists, devices for discovering nanostructures and manipulating atoms become tools for rendering the invisible visible and deconstructing the dynamics of perception itself. 

The expansive goals of the class are tempered by an in-built criticality. “ACT has a unique position as an art program nested within a huge scientific institute — and the challenges of that partnership should not be underestimated,” reflects Putrih. “Science and art are wholly different knowledge systems with distinct historical perspectives. So, how do we communicate? How do we locate that middle ground, that third space?”

An evolving answer, tested and developed throughout the partnership between ACT and MIT.nano, involves a combination of attentive mentorship and sharing of artistic ideas, combined with access to advanced technological resources and hands-on practical training. 

“MIT.nano currently accommodates more than 1,200 individuals to do their work, across 250 different research groups,” says Bulović. “The fact that we count artists among those is a matter of pride for us. We’ve found that the work of our scientists and technologists is enhanced by having access to the language of art as a form of expression — equally, the way that artists express themselves can be stretched beyond what could previously be imagined, simply by having access to the tools and instruments at MIT.nano.”

A playground for experimentation

True to the spirit of the scientific method and artistic iteration, the class is envisioned as a work in progress — a series of propositions and prototypes for how dialogue between scientists and artists might work in practice. The outcomes of those experiments can now be seen installed in the first and second floor galleries at MIT.nano. As part of the facility’s five-year anniversary celebration, the class premiered an exhibition showcasing works created during previous years of “Creating Art, Thinking Science.” 

Visitors to the exhibition, “zero.zerozerozerozerozerozerozerozeroone” (named for the numerical notation for one nanometer), will encounter artworks ranging from a minimalist silicon wafer produced with two-photon polymerization (2PP) technology (“Obscured Invisibility,” 2021, Hyun Woo Park), to traces of an attempt to make vegetable soup in the cleanroom using equipment such as a cryostat, a fluorescing microscope, and a Micro-CT scanner (“May I Please Make You Some Soup?,” 2022, Simone Lasser). 

These works set a precedent for the artworks produced during the fall 2023 iteration of the class. For Ryan Yang, in his senior year studying electrical engineering and computer science at MIT, the chance to engage in open discussion and experimental making has been a rare opportunity to “try something that might not work.” His project explores the possibilities of translating traditional block printing techniques to micron-scale 3D-printing in the MIT.nano labs.

Yang has taken advantage of the arts curriculum at MIT at an early stage in his academic career as an engineer; meanwhile, Ameen Kaleem started out as a filmmaker in New Delhi and is now pursuing a master’s degree in design engineering at Harvard GSD, cross-registered at MIT. 

Kaleem’s project models the process of abiogenesis (the evolution of living organisms from inorganic or inanimate substances) by bringing living moss into the MIT.nano cleanroom facilities to be examined at an atomic scale. “I was interested in the idea that, as a human being in the cleanroom, you are both the most sanitized version of yourself and the dirtiest thing in that space,” she reflects. “Drawing attention to the presence of organic life in the cleanroom is comparable to bringing art into spaces where it might not otherwise exist — a way of humanizing scientific and technological endeavors.”

Consciousness, immersion, and innovation

The students draw upon the legacies of landmark art-science initiatives — including international exhibitions such as “Cybernetic Serendipity” (London ICA, 1968), the “New Tendencies” series (Zagreb, 1961-73), and “Laboratorium” (Antwerp, 1999) — and take inspiration from the instructors’ own creative investigations of the inner workings of different knowledge systems. “In contemporary life, and at MIT in particular, we’re immersed in technology,” says Putrih. “It’s the nature of art to reveal that to us, so that we might see the implications of what we are producing and its potential impact.”

By fostering a mindset of imagination and criticality, combined with building the technical skills to address practical problems, “Creating Art, Thinking Science” seeks to create the conditions for a more expansive version of technological optimism; a culture of innovation in which social and environmental responsibility are seen as productive parameters for enriched creativity. The ripple effects of the class might be years in the making, but as Bulović observes while navigating the exhibition at MIT.nano, “The joy of the collaboration can be felt in the artworks.”

© Photo courtesy of MIT CAST.

Two students engage with an artwork created in 4.373/4.374 (Creating Art, Thinking Science).

Researchers harness 2D magnetic materials for energy-efficient computing

Experimental computer memories and processors built from magnetic materials use far less energy than traditional silicon-based devices. Two-dimensional magnetic materials, composed of layers that are only a few atoms thick, have incredible properties that could allow magnetic-based devices to achieve unprecedented speed, efficiency, and scalability.

While many hurdles must be overcome until these so-called van der Waals magnetic materials can be integrated into functioning computers, MIT researchers took an important step in this direction by demonstrating precise control of a van der Waals magnet at room temperature.

This is key, since magnets composed of atomically thin van der Waals materials can typically only be controlled at extremely cold temperatures, making them difficult to deploy outside a laboratory.

The researchers used pulses of electrical current to switch the direction of the device’s magnetization at room temperature. Magnetic switching can be used in computation, the same way a transistor switches between open and closed to represent 0s and 1s in binary code, or in computer memory, where switching enables data storage.

The team fired bursts of electrons at a magnet made of a new material that can sustain its magnetism at higher temperatures. The experiment leveraged a fundamental property of electrons known as spin, which makes the electrons behave like tiny magnets. By manipulating the spin of electrons that strike the device, the researchers can switch its magnetization.

“The heterostructure device we have developed requires an order of magnitude lower electrical current to switch the van der Waals magnet, compared to that required for bulk magnetic devices,” says Deblina Sarkar, the AT&T Career Development Assistant Professor in the MIT Media Lab and Center for Neurobiological Engineering, head of the Nano-Cybernetic Biotrek Lab, and the senior author of a paper on this technique. “Our device is also more energy efficient than other van der Waals magnets that are unable to switch at room temperature.”

In the future, such a magnet could be used to build faster computers that consume less electricity. It could also enable magnetic computer memories that are nonvolatile, which means they don’t leak information when powered off, or processors that make complex AI algorithms more energy-efficient.

“There is a lot of inertia around trying to improve materials that worked well in the past. But we have shown that if you make radical changes, starting by rethinking the materials you are using, you can potentially get much better solutions,” says Shivam Kajale, a graduate student in Sarkar’s lab and co-lead author of the paper.

Kajale and Sarkar are joined on the paper by co-lead author Thanh Nguyen, a graduate student in the Department of Nuclear Science and Engineering (NSE); Corson Chao, a graduate student in the Department of Materials Science and Engineering (DSME); David Bono, a DSME research scientist; Artittaya Boonkird, an NSE graduate student; and Mingda Li, associate professor of nuclear science and engineering. The research appears this week in Nature Communications.

An atomically thin advantage

Methods to fabricate tiny computer chips in a clean room from bulk materials like silicon can hamper devices. For instance, the layers of material may be barely 1 nanometer thick, so minuscule rough spots on the surface can be severe enough to degrade performance.

By contrast, van der Waals magnetic materials are intrinsically layered and structured in such a way that the surface remains perfectly smooth, even as researchers peel off layers to make thinner devices. In addition, atoms in one layer won’t leak into other layers, enabling the materials to retain their unique properties when stacked in devices.

“In terms of scaling and making these magnetic devices competitive for commercial applications, van der Waals materials are the way to go,” Kajale says.

But there’s a catch. This new class of magnetic materials have typically only been operated at temperatures below 60 kelvins (-351 degrees Fahrenheit). To build a magnetic computer processor or memory, researchers need to use electrical current to operate the magnet at room temperature.

To achieve this, the team focused on an emerging material called iron gallium telluride. This atomically thin material has all the properties needed for effective room temperature magnetism and doesn’t contain rare earth elements, which are undesirable because extracting them is especially destructive to the environment.

Nguyen carefully grew bulk crystals of this 2D material using a special technique. Then, Kajale fabricated a two-layer magnetic device using nanoscale flakes of iron gallium telluride underneath a six-nanometer layer of platinum.

Tiny device in hand, they used an intrinsic property of electrons known as spin to switch its magnetization at room temperature.

Electron ping-pong

While electrons don’t technically “spin” like a top, they do possess the same kind of angular momentum. That spin has a direction, either up or down. The researchers can leverage a property known as spin-orbit coupling to control the spins of electrons they fire at the magnet.

The same way momentum is transferred when one ball hits another, electrons will transfer their “spin momentum” to the 2D magnetic material when they strike it. Depending on the direction of their spins, that momentum transfer can reverse the magnetization.

In a sense, this transfer rotates the magnetization from up to down (or vice-versa), so it is called a “torque,” as in spin-orbit torque switching. Applying a negative electric pulse causes the magnetization to go downward, while a positive pulse causes it to go upward.

The researchers can do this switching at room temperature for two reasons: the special properties of iron gallium telluride and the fact that their technique uses small amounts of electrical current. Pumping too much current into the device would cause it to overheat and demagnetize.

The team faced many challenges over the two years it took to achieve this milestone, Kajale says. Finding the right magnetic material was only half the battle. Since iron gallium telluride oxidizes quickly, fabrication must be done inside a glovebox filled with nitrogen.

“The device is only exposed to air for 10 or 15 seconds, but even after that I have to do a step where I polish it to remove any oxide,” he says.

Now that they have demonstrated room-temperature switching and greater energy efficiency, the researchers plan to keep pushing the performance of magnetic van der Waals materials.

“Our next milestone is to achieve switching without the need for any external magnetic fields. Our aim is to enhance our technology and scale up to bring the versatility of van der Waals magnet to commercial applications,” Sarkar says.

This work was carried out, in part, using the facilities at MIT.Nano and the Harvard University Center for Nanoscale Systems.

© Image: Courtesy of the researchers

This illustration shows electric current being pumped into platinum (the bottom slab), which results in the creation of an electron spin current that switches the magnetic state of the 2D ferromagnet on top. The colored spheres represent the atoms in the 2D material.
  • ✇MIT News - Nanoscience and nanotechnology | MIT.nano
  • Propelling atomically layered magnets toward green computersMedia Lab
    Globally, computation is booming at an unprecedented rate, fueled by the boons of artificial intelligence. With this, the staggering energy demand of the world’s computing infrastructure has become a major concern, and the development of computing devices that are far more energy-efficient is a leading challenge for the scientific community.  Use of magnetic materials to build computing devices like memories and processors has emerged as a promising avenue for creating “beyond-CMOS” computers,
     

Propelling atomically layered magnets toward green computers

Globally, computation is booming at an unprecedented rate, fueled by the boons of artificial intelligence. With this, the staggering energy demand of the world’s computing infrastructure has become a major concern, and the development of computing devices that are far more energy-efficient is a leading challenge for the scientific community. 

Use of magnetic materials to build computing devices like memories and processors has emerged as a promising avenue for creating “beyond-CMOS” computers, which would use far less energy compared to traditional computers. Magnetization switching in magnets can be used in computation the same way that a transistor switches from open or closed to represent the 0s and 1s of binary code. 

While much of the research along this direction has focused on using bulk magnetic materials, a new class of magnetic materials — called two-dimensional van der Waals magnets — provides superior properties that can improve the scalability and energy efficiency of magnetic devices to make them commercially viable. 

Although the benefits of shifting to 2D magnetic materials are evident, their practical induction into computers has been hindered by some fundamental challenges. Until recently, 2D magnetic materials could operate only at very low temperatures, much like superconductors. So bringing their operating temperatures above room temperature has remained a primary goal. Additionally, for use in computers, it is important that they can be controlled electrically, without the need for magnetic fields. Bridging this fundamental gap, where 2D magnetic materials can be electrically switched above room temperature without any magnetic fields, could potentially catapult the translation of 2D magnets into the next generation of “green” computers.

A team of MIT researchers has now achieved this critical milestone by designing a “van der Waals atomically layered heterostructure” device where a 2D van der Waals magnet, iron gallium telluride, is interfaced with another 2D material, tungsten ditelluride. In an open-access paper published March 15 in Science Advances, the team shows that the magnet can be toggled between the 0 and 1 states simply by applying pulses of electrical current across their two-layer device. 

“Our device enables robust magnetization switching without the need for an external magnetic field, opening up unprecedented opportunities for ultra-low power and environmentally sustainable computing technology for big data and AI,” says lead author Deblina Sarkar, the AT&T Career Development Assistant Professor at the MIT Media Lab and Center for Neurobiological Engineering, and head of the Nano-Cybernetic Biotrek research group. “Moreover, the atomically layered structure of our device provides unique capabilities including improved interface and possibilities of gate voltage tunability, as well as flexible and transparent spintronic technologies.”

Sarkar is joined on the paper by first author Shivam Kajale, a graduate student in Sarkar’s research group at the Media Lab; Thanh Nguyen, a graduate student in the Department of Nuclear Science and Engineering (NSE); Nguyen Tuan Hung, an MIT visiting scholar in NSE and an assistant professor at Tohoku University in Japan; and Mingda Li, associate professor of NSE.

Breaking the mirror symmetries 

When electric current flows through heavy metals like platinum or tantalum, the electrons get segregated in the materials based on their spin component, a phenomenon called the spin Hall effect, says Kajale. The way this segregation happens depends on the material, and particularly its symmetries.

“The conversion of electric current to spin currents in heavy metals lies at the heart of controlling magnets electrically,” Kajale notes. “The microscopic structure of conventionally used materials, like platinum, have a kind of mirror symmetry, which restricts the spin currents only to in-plane spin polarization.”

Kajale explains that two mirror symmetries must be broken to produce an “out-of-plane” spin component that can be transferred to a magnetic layer to induce field-free switching. “Electrical current can 'break' the mirror symmetry along one plane in platinum, but its crystal structure prevents the mirror symmetry from being broken in a second plane.”

In their earlier experiments, the researchers used a small magnetic field to break the second mirror plane. To get rid of the need for a magnetic nudge, Kajale and Sarkar and colleagues looked instead for a material with a structure that could break the second mirror plane without outside help. This led them to another 2D material, tungsten ditelluride. The tungsten ditelluride that the researchers used has an orthorhombic crystal structure. The material itself has one broken mirror plane. Thus, by applying current along its low-symmetry axis (parallel to the broken mirror plane), the resulting spin current has an out-of-plane spin component that can directly induce switching in the ultra-thin magnet interfaced with the tungsten ditelluride. 

“Because it's also a 2D van der Waals material, it can also ensure that when we stack the two materials together, we get pristine interfaces and a good flow of electron spins between the materials,” says Kajale. 

Becoming more energy-efficient 

Computer memory and processors built from magnetic materials use less energy than traditional silicon-based devices. And the van der Waals magnets can offer higher energy efficiency and better scalability compared to bulk magnetic material, the researchers note. 

The electrical current density used for switching the magnet translates to how much energy is dissipated during switching. A lower density means a much more energy-efficient material. “The new design has one of the lowest current densities in van der Waals magnetic materials,” Kajale says. “This new design has an order of magnitude lower in terms of the switching current required in bulk materials. This translates to something like two orders of magnitude improvement in energy efficiency.”

The research team is now looking at similar low-symmetry van der Waals materials to see if they can reduce current density even further. They are also hoping to collaborate with other researchers to find ways to manufacture the 2D magnetic switch devices at commercial scale. 

This work was carried out, in part, using the facilities at MIT.nano. It was funded by the Media Lab, the U.S. National Science Foundation, and the U.S. Department of Energy.

© Image courtesy of the researchers.

The flow of electrical current in the bottom crystalline slab (representing WTe2) breaks a mirror symmetry (shattered glass), while the material itself breaks the other mirror symmetry (cracked glass). The resulting spin current has vertical polarization that switches the magnetic state of the top 2D ferromagnet.

Creative collisions: Crossing the art-science divide

MIT has a rich history of productive collaboration between the arts and the sciences, anchored by the conviction that these two conventionally opposed ways of thinking can form a deeply generative symbiosis that serves to advance and humanize new technologies. 

This ethos was made tangible when the Bauhaus artist and educator György Kepes established the MIT Center for Advanced Visual Studies (CAVS) within the Department of Architecture in 1967. CAVS has since evolved into the Art, Culture, and Technology (ACT) program, which fosters close links to multiple other programs, centers, and labs at MIT. Class 4.373/4.374 (Creating Art, Thinking Science), open to undergraduates and master’s students of all disciplines as well as certain students from the Harvard Graduate School of Design (GSD), is one of the program’s most innovative offerings, proposing a model for how the relationship between art and science might play out at a time of exponential technological growth. 

Now in its third year, the class is supported by an Interdisciplinary Class Development Grant from the MIT Center for Art, Science and Technology (CAST) and draws upon the unparalleled resources of MIT.nano; an artist’s high-tech toolbox for investigating the hidden structures and beauty of our material universe.

High ambitions and critical thinking

The class was initiated by Tobias Putrih, lecturer in ACT, and is taught with the assistance of Ardalan SadeghiKivi MArch ’23, and Aubrie James SM ’24. Central to the success of the class has been the collaboration with co-instructor Vladimir Bulović, the founding director of MIT.nano and Fariborz Maseeh Chair in Emerging Technology, who has positioned the facility as an open-access resource for the campus at large — including MIT’s community of artists. “Creating Art, Thinking Science” unfolds the 100,000 square feet of cleanroom and lab space within the Lisa T. Su Building, inviting participating students to take advantage of cutting-edge equipment for nanoscale visualization and fabrication; in the hands of artists, devices for discovering nanostructures and manipulating atoms become tools for rendering the invisible visible and deconstructing the dynamics of perception itself. 

The expansive goals of the class are tempered by an in-built criticality. “ACT has a unique position as an art program nested within a huge scientific institute — and the challenges of that partnership should not be underestimated,” reflects Putrih. “Science and art are wholly different knowledge systems with distinct historical perspectives. So, how do we communicate? How do we locate that middle ground, that third space?”

An evolving answer, tested and developed throughout the partnership between ACT and MIT.nano, involves a combination of attentive mentorship and sharing of artistic ideas, combined with access to advanced technological resources and hands-on practical training. 

“MIT.nano currently accommodates more than 1,200 individuals to do their work, across 250 different research groups,” says Bulović. “The fact that we count artists among those is a matter of pride for us. We’ve found that the work of our scientists and technologists is enhanced by having access to the language of art as a form of expression — equally, the way that artists express themselves can be stretched beyond what could previously be imagined, simply by having access to the tools and instruments at MIT.nano.”

A playground for experimentation

True to the spirit of the scientific method and artistic iteration, the class is envisioned as a work in progress — a series of propositions and prototypes for how dialogue between scientists and artists might work in practice. The outcomes of those experiments can now be seen installed in the first and second floor galleries at MIT.nano. As part of the facility’s five-year anniversary celebration, the class premiered an exhibition showcasing works created during previous years of “Creating Art, Thinking Science.” 

Visitors to the exhibition, “zero.zerozerozerozerozerozerozerozeroone” (named for the numerical notation for one nanometer), will encounter artworks ranging from a minimalist silicon wafer produced with two-photon polymerization (2PP) technology (“Obscured Invisibility,” 2021, Hyun Woo Park), to traces of an attempt to make vegetable soup in the cleanroom using equipment such as a cryostat, a fluorescing microscope, and a Micro-CT scanner (“May I Please Make You Some Soup?,” 2022, Simone Lasser). 

These works set a precedent for the artworks produced during the fall 2023 iteration of the class. For Ryan Yang, in his senior year studying electrical engineering and computer science at MIT, the chance to engage in open discussion and experimental making has been a rare opportunity to “try something that might not work.” His project explores the possibilities of translating traditional block printing techniques to micron-scale 3D-printing in the MIT.nano labs.

Yang has taken advantage of the arts curriculum at MIT at an early stage in his academic career as an engineer; meanwhile, Ameen Kaleem started out as a filmmaker in New Delhi and is now pursuing a master’s degree in design engineering at Harvard GSD, cross-registered at MIT. 

Kaleem’s project models the process of abiogenesis (the evolution of living organisms from inorganic or inanimate substances) by bringing living moss into the MIT.nano cleanroom facilities to be examined at an atomic scale. “I was interested in the idea that, as a human being in the cleanroom, you are both the most sanitized version of yourself and the dirtiest thing in that space,” she reflects. “Drawing attention to the presence of organic life in the cleanroom is comparable to bringing art into spaces where it might not otherwise exist — a way of humanizing scientific and technological endeavors.”

Consciousness, immersion, and innovation

The students draw upon the legacies of landmark art-science initiatives — including international exhibitions such as “Cybernetic Serendipity” (London ICA, 1968), the “New Tendencies” series (Zagreb, 1961-73), and “Laboratorium” (Antwerp, 1999) — and take inspiration from the instructors’ own creative investigations of the inner workings of different knowledge systems. “In contemporary life, and at MIT in particular, we’re immersed in technology,” says Putrih. “It’s the nature of art to reveal that to us, so that we might see the implications of what we are producing and its potential impact.”

By fostering a mindset of imagination and criticality, combined with building the technical skills to address practical problems, “Creating Art, Thinking Science” seeks to create the conditions for a more expansive version of technological optimism; a culture of innovation in which social and environmental responsibility are seen as productive parameters for enriched creativity. The ripple effects of the class might be years in the making, but as Bulović observes while navigating the exhibition at MIT.nano, “The joy of the collaboration can be felt in the artworks.”

© Photo courtesy of MIT CAST.

Two students engage with an artwork created in 4.373/4.374 (Creating Art, Thinking Science).

Researchers harness 2D magnetic materials for energy-efficient computing

Experimental computer memories and processors built from magnetic materials use far less energy than traditional silicon-based devices. Two-dimensional magnetic materials, composed of layers that are only a few atoms thick, have incredible properties that could allow magnetic-based devices to achieve unprecedented speed, efficiency, and scalability.

While many hurdles must be overcome until these so-called van der Waals magnetic materials can be integrated into functioning computers, MIT researchers took an important step in this direction by demonstrating precise control of a van der Waals magnet at room temperature.

This is key, since magnets composed of atomically thin van der Waals materials can typically only be controlled at extremely cold temperatures, making them difficult to deploy outside a laboratory.

The researchers used pulses of electrical current to switch the direction of the device’s magnetization at room temperature. Magnetic switching can be used in computation, the same way a transistor switches between open and closed to represent 0s and 1s in binary code, or in computer memory, where switching enables data storage.

The team fired bursts of electrons at a magnet made of a new material that can sustain its magnetism at higher temperatures. The experiment leveraged a fundamental property of electrons known as spin, which makes the electrons behave like tiny magnets. By manipulating the spin of electrons that strike the device, the researchers can switch its magnetization.

“The heterostructure device we have developed requires an order of magnitude lower electrical current to switch the van der Waals magnet, compared to that required for bulk magnetic devices,” says Deblina Sarkar, the AT&T Career Development Assistant Professor in the MIT Media Lab and Center for Neurobiological Engineering, head of the Nano-Cybernetic Biotrek Lab, and the senior author of a paper on this technique. “Our device is also more energy efficient than other van der Waals magnets that are unable to switch at room temperature.”

In the future, such a magnet could be used to build faster computers that consume less electricity. It could also enable magnetic computer memories that are nonvolatile, which means they don’t leak information when powered off, or processors that make complex AI algorithms more energy-efficient.

“There is a lot of inertia around trying to improve materials that worked well in the past. But we have shown that if you make radical changes, starting by rethinking the materials you are using, you can potentially get much better solutions,” says Shivam Kajale, a graduate student in Sarkar’s lab and co-lead author of the paper.

Kajale and Sarkar are joined on the paper by co-lead author Thanh Nguyen, a graduate student in the Department of Nuclear Science and Engineering (NSE); Corson Chao, a graduate student in the Department of Materials Science and Engineering (DSME); David Bono, a DSME research scientist; Artittaya Boonkird, an NSE graduate student; and Mingda Li, associate professor of nuclear science and engineering. The research appears this week in Nature Communications.

An atomically thin advantage

Methods to fabricate tiny computer chips in a clean room from bulk materials like silicon can hamper devices. For instance, the layers of material may be barely 1 nanometer thick, so minuscule rough spots on the surface can be severe enough to degrade performance.

By contrast, van der Waals magnetic materials are intrinsically layered and structured in such a way that the surface remains perfectly smooth, even as researchers peel off layers to make thinner devices. In addition, atoms in one layer won’t leak into other layers, enabling the materials to retain their unique properties when stacked in devices.

“In terms of scaling and making these magnetic devices competitive for commercial applications, van der Waals materials are the way to go,” Kajale says.

But there’s a catch. This new class of magnetic materials have typically only been operated at temperatures below 60 kelvins (-351 degrees Fahrenheit). To build a magnetic computer processor or memory, researchers need to use electrical current to operate the magnet at room temperature.

To achieve this, the team focused on an emerging material called iron gallium telluride. This atomically thin material has all the properties needed for effective room temperature magnetism and doesn’t contain rare earth elements, which are undesirable because extracting them is especially destructive to the environment.

Nguyen carefully grew bulk crystals of this 2D material using a special technique. Then, Kajale fabricated a two-layer magnetic device using nanoscale flakes of iron gallium telluride underneath a six-nanometer layer of platinum.

Tiny device in hand, they used an intrinsic property of electrons known as spin to switch its magnetization at room temperature.

Electron ping-pong

While electrons don’t technically “spin” like a top, they do possess the same kind of angular momentum. That spin has a direction, either up or down. The researchers can leverage a property known as spin-orbit coupling to control the spins of electrons they fire at the magnet.

The same way momentum is transferred when one ball hits another, electrons will transfer their “spin momentum” to the 2D magnetic material when they strike it. Depending on the direction of their spins, that momentum transfer can reverse the magnetization.

In a sense, this transfer rotates the magnetization from up to down (or vice-versa), so it is called a “torque,” as in spin-orbit torque switching. Applying a negative electric pulse causes the magnetization to go downward, while a positive pulse causes it to go upward.

The researchers can do this switching at room temperature for two reasons: the special properties of iron gallium telluride and the fact that their technique uses small amounts of electrical current. Pumping too much current into the device would cause it to overheat and demagnetize.

The team faced many challenges over the two years it took to achieve this milestone, Kajale says. Finding the right magnetic material was only half the battle. Since iron gallium telluride oxidizes quickly, fabrication must be done inside a glovebox filled with nitrogen.

“The device is only exposed to air for 10 or 15 seconds, but even after that I have to do a step where I polish it to remove any oxide,” he says.

Now that they have demonstrated room-temperature switching and greater energy efficiency, the researchers plan to keep pushing the performance of magnetic van der Waals materials.

“Our next milestone is to achieve switching without the need for any external magnetic fields. Our aim is to enhance our technology and scale up to bring the versatility of van der Waals magnet to commercial applications,” Sarkar says.

This work was carried out, in part, using the facilities at MIT.Nano and the Harvard University Center for Nanoscale Systems.

© Image: Courtesy of the researchers

This illustration shows electric current being pumped into platinum (the bottom slab), which results in the creation of an electron spin current that switches the magnetic state of the 2D ferromagnet on top. The colored spheres represent the atoms in the 2D material.
  • ✇MIT News - Nanoscience and nanotechnology | MIT.nano
  • Propelling atomically layered magnets toward green computersMedia Lab
    Globally, computation is booming at an unprecedented rate, fueled by the boons of artificial intelligence. With this, the staggering energy demand of the world’s computing infrastructure has become a major concern, and the development of computing devices that are far more energy-efficient is a leading challenge for the scientific community.  Use of magnetic materials to build computing devices like memories and processors has emerged as a promising avenue for creating “beyond-CMOS” computers,
     

Propelling atomically layered magnets toward green computers

Globally, computation is booming at an unprecedented rate, fueled by the boons of artificial intelligence. With this, the staggering energy demand of the world’s computing infrastructure has become a major concern, and the development of computing devices that are far more energy-efficient is a leading challenge for the scientific community. 

Use of magnetic materials to build computing devices like memories and processors has emerged as a promising avenue for creating “beyond-CMOS” computers, which would use far less energy compared to traditional computers. Magnetization switching in magnets can be used in computation the same way that a transistor switches from open or closed to represent the 0s and 1s of binary code. 

While much of the research along this direction has focused on using bulk magnetic materials, a new class of magnetic materials — called two-dimensional van der Waals magnets — provides superior properties that can improve the scalability and energy efficiency of magnetic devices to make them commercially viable. 

Although the benefits of shifting to 2D magnetic materials are evident, their practical induction into computers has been hindered by some fundamental challenges. Until recently, 2D magnetic materials could operate only at very low temperatures, much like superconductors. So bringing their operating temperatures above room temperature has remained a primary goal. Additionally, for use in computers, it is important that they can be controlled electrically, without the need for magnetic fields. Bridging this fundamental gap, where 2D magnetic materials can be electrically switched above room temperature without any magnetic fields, could potentially catapult the translation of 2D magnets into the next generation of “green” computers.

A team of MIT researchers has now achieved this critical milestone by designing a “van der Waals atomically layered heterostructure” device where a 2D van der Waals magnet, iron gallium telluride, is interfaced with another 2D material, tungsten ditelluride. In an open-access paper published March 15 in Science Advances, the team shows that the magnet can be toggled between the 0 and 1 states simply by applying pulses of electrical current across their two-layer device. 

“Our device enables robust magnetization switching without the need for an external magnetic field, opening up unprecedented opportunities for ultra-low power and environmentally sustainable computing technology for big data and AI,” says lead author Deblina Sarkar, the AT&T Career Development Assistant Professor at the MIT Media Lab and Center for Neurobiological Engineering, and head of the Nano-Cybernetic Biotrek research group. “Moreover, the atomically layered structure of our device provides unique capabilities including improved interface and possibilities of gate voltage tunability, as well as flexible and transparent spintronic technologies.”

Sarkar is joined on the paper by first author Shivam Kajale, a graduate student in Sarkar’s research group at the Media Lab; Thanh Nguyen, a graduate student in the Department of Nuclear Science and Engineering (NSE); Nguyen Tuan Hung, an MIT visiting scholar in NSE and an assistant professor at Tohoku University in Japan; and Mingda Li, associate professor of NSE.

Breaking the mirror symmetries 

When electric current flows through heavy metals like platinum or tantalum, the electrons get segregated in the materials based on their spin component, a phenomenon called the spin Hall effect, says Kajale. The way this segregation happens depends on the material, and particularly its symmetries.

“The conversion of electric current to spin currents in heavy metals lies at the heart of controlling magnets electrically,” Kajale notes. “The microscopic structure of conventionally used materials, like platinum, have a kind of mirror symmetry, which restricts the spin currents only to in-plane spin polarization.”

Kajale explains that two mirror symmetries must be broken to produce an “out-of-plane” spin component that can be transferred to a magnetic layer to induce field-free switching. “Electrical current can 'break' the mirror symmetry along one plane in platinum, but its crystal structure prevents the mirror symmetry from being broken in a second plane.”

In their earlier experiments, the researchers used a small magnetic field to break the second mirror plane. To get rid of the need for a magnetic nudge, Kajale and Sarkar and colleagues looked instead for a material with a structure that could break the second mirror plane without outside help. This led them to another 2D material, tungsten ditelluride. The tungsten ditelluride that the researchers used has an orthorhombic crystal structure. The material itself has one broken mirror plane. Thus, by applying current along its low-symmetry axis (parallel to the broken mirror plane), the resulting spin current has an out-of-plane spin component that can directly induce switching in the ultra-thin magnet interfaced with the tungsten ditelluride. 

“Because it's also a 2D van der Waals material, it can also ensure that when we stack the two materials together, we get pristine interfaces and a good flow of electron spins between the materials,” says Kajale. 

Becoming more energy-efficient 

Computer memory and processors built from magnetic materials use less energy than traditional silicon-based devices. And the van der Waals magnets can offer higher energy efficiency and better scalability compared to bulk magnetic material, the researchers note. 

The electrical current density used for switching the magnet translates to how much energy is dissipated during switching. A lower density means a much more energy-efficient material. “The new design has one of the lowest current densities in van der Waals magnetic materials,” Kajale says. “This new design has an order of magnitude lower in terms of the switching current required in bulk materials. This translates to something like two orders of magnitude improvement in energy efficiency.”

The research team is now looking at similar low-symmetry van der Waals materials to see if they can reduce current density even further. They are also hoping to collaborate with other researchers to find ways to manufacture the 2D magnetic switch devices at commercial scale. 

This work was carried out, in part, using the facilities at MIT.nano. It was funded by the Media Lab, the U.S. National Science Foundation, and the U.S. Department of Energy.

© Image courtesy of the researchers.

The flow of electrical current in the bottom crystalline slab (representing WTe2) breaks a mirror symmetry (shattered glass), while the material itself breaks the other mirror symmetry (cracked glass). The resulting spin current has vertical polarization that switches the magnetic state of the top 2D ferromagnet.

Creative collisions: Crossing the art-science divide

MIT has a rich history of productive collaboration between the arts and the sciences, anchored by the conviction that these two conventionally opposed ways of thinking can form a deeply generative symbiosis that serves to advance and humanize new technologies. 

This ethos was made tangible when the Bauhaus artist and educator György Kepes established the MIT Center for Advanced Visual Studies (CAVS) within the Department of Architecture in 1967. CAVS has since evolved into the Art, Culture, and Technology (ACT) program, which fosters close links to multiple other programs, centers, and labs at MIT. Class 4.373/4.374 (Creating Art, Thinking Science), open to undergraduates and master’s students of all disciplines as well as certain students from the Harvard Graduate School of Design (GSD), is one of the program’s most innovative offerings, proposing a model for how the relationship between art and science might play out at a time of exponential technological growth. 

Now in its third year, the class is supported by an Interdisciplinary Class Development Grant from the MIT Center for Art, Science and Technology (CAST) and draws upon the unparalleled resources of MIT.nano; an artist’s high-tech toolbox for investigating the hidden structures and beauty of our material universe.

High ambitions and critical thinking

The class was initiated by Tobias Putrih, lecturer in ACT, and is taught with the assistance of Ardalan SadeghiKivi MArch ’23, and Aubrie James SM ’24. Central to the success of the class has been the collaboration with co-instructor Vladimir Bulović, the founding director of MIT.nano and Fariborz Maseeh Chair in Emerging Technology, who has positioned the facility as an open-access resource for the campus at large — including MIT’s community of artists. “Creating Art, Thinking Science” unfolds the 100,000 square feet of cleanroom and lab space within the Lisa T. Su Building, inviting participating students to take advantage of cutting-edge equipment for nanoscale visualization and fabrication; in the hands of artists, devices for discovering nanostructures and manipulating atoms become tools for rendering the invisible visible and deconstructing the dynamics of perception itself. 

The expansive goals of the class are tempered by an in-built criticality. “ACT has a unique position as an art program nested within a huge scientific institute — and the challenges of that partnership should not be underestimated,” reflects Putrih. “Science and art are wholly different knowledge systems with distinct historical perspectives. So, how do we communicate? How do we locate that middle ground, that third space?”

An evolving answer, tested and developed throughout the partnership between ACT and MIT.nano, involves a combination of attentive mentorship and sharing of artistic ideas, combined with access to advanced technological resources and hands-on practical training. 

“MIT.nano currently accommodates more than 1,200 individuals to do their work, across 250 different research groups,” says Bulović. “The fact that we count artists among those is a matter of pride for us. We’ve found that the work of our scientists and technologists is enhanced by having access to the language of art as a form of expression — equally, the way that artists express themselves can be stretched beyond what could previously be imagined, simply by having access to the tools and instruments at MIT.nano.”

A playground for experimentation

True to the spirit of the scientific method and artistic iteration, the class is envisioned as a work in progress — a series of propositions and prototypes for how dialogue between scientists and artists might work in practice. The outcomes of those experiments can now be seen installed in the first and second floor galleries at MIT.nano. As part of the facility’s five-year anniversary celebration, the class premiered an exhibition showcasing works created during previous years of “Creating Art, Thinking Science.” 

Visitors to the exhibition, “zero.zerozerozerozerozerozerozerozeroone” (named for the numerical notation for one nanometer), will encounter artworks ranging from a minimalist silicon wafer produced with two-photon polymerization (2PP) technology (“Obscured Invisibility,” 2021, Hyun Woo Park), to traces of an attempt to make vegetable soup in the cleanroom using equipment such as a cryostat, a fluorescing microscope, and a Micro-CT scanner (“May I Please Make You Some Soup?,” 2022, Simone Lasser). 

These works set a precedent for the artworks produced during the fall 2023 iteration of the class. For Ryan Yang, in his senior year studying electrical engineering and computer science at MIT, the chance to engage in open discussion and experimental making has been a rare opportunity to “try something that might not work.” His project explores the possibilities of translating traditional block printing techniques to micron-scale 3D-printing in the MIT.nano labs.

Yang has taken advantage of the arts curriculum at MIT at an early stage in his academic career as an engineer; meanwhile, Ameen Kaleem started out as a filmmaker in New Delhi and is now pursuing a master’s degree in design engineering at Harvard GSD, cross-registered at MIT. 

Kaleem’s project models the process of abiogenesis (the evolution of living organisms from inorganic or inanimate substances) by bringing living moss into the MIT.nano cleanroom facilities to be examined at an atomic scale. “I was interested in the idea that, as a human being in the cleanroom, you are both the most sanitized version of yourself and the dirtiest thing in that space,” she reflects. “Drawing attention to the presence of organic life in the cleanroom is comparable to bringing art into spaces where it might not otherwise exist — a way of humanizing scientific and technological endeavors.”

Consciousness, immersion, and innovation

The students draw upon the legacies of landmark art-science initiatives — including international exhibitions such as “Cybernetic Serendipity” (London ICA, 1968), the “New Tendencies” series (Zagreb, 1961-73), and “Laboratorium” (Antwerp, 1999) — and take inspiration from the instructors’ own creative investigations of the inner workings of different knowledge systems. “In contemporary life, and at MIT in particular, we’re immersed in technology,” says Putrih. “It’s the nature of art to reveal that to us, so that we might see the implications of what we are producing and its potential impact.”

By fostering a mindset of imagination and criticality, combined with building the technical skills to address practical problems, “Creating Art, Thinking Science” seeks to create the conditions for a more expansive version of technological optimism; a culture of innovation in which social and environmental responsibility are seen as productive parameters for enriched creativity. The ripple effects of the class might be years in the making, but as Bulović observes while navigating the exhibition at MIT.nano, “The joy of the collaboration can be felt in the artworks.”

© Photo courtesy of MIT CAST.

Two students engage with an artwork created in 4.373/4.374 (Creating Art, Thinking Science).

Researchers harness 2D magnetic materials for energy-efficient computing

Experimental computer memories and processors built from magnetic materials use far less energy than traditional silicon-based devices. Two-dimensional magnetic materials, composed of layers that are only a few atoms thick, have incredible properties that could allow magnetic-based devices to achieve unprecedented speed, efficiency, and scalability.

While many hurdles must be overcome until these so-called van der Waals magnetic materials can be integrated into functioning computers, MIT researchers took an important step in this direction by demonstrating precise control of a van der Waals magnet at room temperature.

This is key, since magnets composed of atomically thin van der Waals materials can typically only be controlled at extremely cold temperatures, making them difficult to deploy outside a laboratory.

The researchers used pulses of electrical current to switch the direction of the device’s magnetization at room temperature. Magnetic switching can be used in computation, the same way a transistor switches between open and closed to represent 0s and 1s in binary code, or in computer memory, where switching enables data storage.

The team fired bursts of electrons at a magnet made of a new material that can sustain its magnetism at higher temperatures. The experiment leveraged a fundamental property of electrons known as spin, which makes the electrons behave like tiny magnets. By manipulating the spin of electrons that strike the device, the researchers can switch its magnetization.

“The heterostructure device we have developed requires an order of magnitude lower electrical current to switch the van der Waals magnet, compared to that required for bulk magnetic devices,” says Deblina Sarkar, the AT&T Career Development Assistant Professor in the MIT Media Lab and Center for Neurobiological Engineering, head of the Nano-Cybernetic Biotrek Lab, and the senior author of a paper on this technique. “Our device is also more energy efficient than other van der Waals magnets that are unable to switch at room temperature.”

In the future, such a magnet could be used to build faster computers that consume less electricity. It could also enable magnetic computer memories that are nonvolatile, which means they don’t leak information when powered off, or processors that make complex AI algorithms more energy-efficient.

“There is a lot of inertia around trying to improve materials that worked well in the past. But we have shown that if you make radical changes, starting by rethinking the materials you are using, you can potentially get much better solutions,” says Shivam Kajale, a graduate student in Sarkar’s lab and co-lead author of the paper.

Kajale and Sarkar are joined on the paper by co-lead author Thanh Nguyen, a graduate student in the Department of Nuclear Science and Engineering (NSE); Corson Chao, a graduate student in the Department of Materials Science and Engineering (DSME); David Bono, a DSME research scientist; Artittaya Boonkird, an NSE graduate student; and Mingda Li, associate professor of nuclear science and engineering. The research appears this week in Nature Communications.

An atomically thin advantage

Methods to fabricate tiny computer chips in a clean room from bulk materials like silicon can hamper devices. For instance, the layers of material may be barely 1 nanometer thick, so minuscule rough spots on the surface can be severe enough to degrade performance.

By contrast, van der Waals magnetic materials are intrinsically layered and structured in such a way that the surface remains perfectly smooth, even as researchers peel off layers to make thinner devices. In addition, atoms in one layer won’t leak into other layers, enabling the materials to retain their unique properties when stacked in devices.

“In terms of scaling and making these magnetic devices competitive for commercial applications, van der Waals materials are the way to go,” Kajale says.

But there’s a catch. This new class of magnetic materials have typically only been operated at temperatures below 60 kelvins (-351 degrees Fahrenheit). To build a magnetic computer processor or memory, researchers need to use electrical current to operate the magnet at room temperature.

To achieve this, the team focused on an emerging material called iron gallium telluride. This atomically thin material has all the properties needed for effective room temperature magnetism and doesn’t contain rare earth elements, which are undesirable because extracting them is especially destructive to the environment.

Nguyen carefully grew bulk crystals of this 2D material using a special technique. Then, Kajale fabricated a two-layer magnetic device using nanoscale flakes of iron gallium telluride underneath a six-nanometer layer of platinum.

Tiny device in hand, they used an intrinsic property of electrons known as spin to switch its magnetization at room temperature.

Electron ping-pong

While electrons don’t technically “spin” like a top, they do possess the same kind of angular momentum. That spin has a direction, either up or down. The researchers can leverage a property known as spin-orbit coupling to control the spins of electrons they fire at the magnet.

The same way momentum is transferred when one ball hits another, electrons will transfer their “spin momentum” to the 2D magnetic material when they strike it. Depending on the direction of their spins, that momentum transfer can reverse the magnetization.

In a sense, this transfer rotates the magnetization from up to down (or vice-versa), so it is called a “torque,” as in spin-orbit torque switching. Applying a negative electric pulse causes the magnetization to go downward, while a positive pulse causes it to go upward.

The researchers can do this switching at room temperature for two reasons: the special properties of iron gallium telluride and the fact that their technique uses small amounts of electrical current. Pumping too much current into the device would cause it to overheat and demagnetize.

The team faced many challenges over the two years it took to achieve this milestone, Kajale says. Finding the right magnetic material was only half the battle. Since iron gallium telluride oxidizes quickly, fabrication must be done inside a glovebox filled with nitrogen.

“The device is only exposed to air for 10 or 15 seconds, but even after that I have to do a step where I polish it to remove any oxide,” he says.

Now that they have demonstrated room-temperature switching and greater energy efficiency, the researchers plan to keep pushing the performance of magnetic van der Waals materials.

“Our next milestone is to achieve switching without the need for any external magnetic fields. Our aim is to enhance our technology and scale up to bring the versatility of van der Waals magnet to commercial applications,” Sarkar says.

This work was carried out, in part, using the facilities at MIT.Nano and the Harvard University Center for Nanoscale Systems.

© Image: Courtesy of the researchers

This illustration shows electric current being pumped into platinum (the bottom slab), which results in the creation of an electron spin current that switches the magnetic state of the 2D ferromagnet on top. The colored spheres represent the atoms in the 2D material.
  • ✇MIT News - Nanoscience and nanotechnology | MIT.nano
  • Propelling atomically layered magnets toward green computersMedia Lab
    Globally, computation is booming at an unprecedented rate, fueled by the boons of artificial intelligence. With this, the staggering energy demand of the world’s computing infrastructure has become a major concern, and the development of computing devices that are far more energy-efficient is a leading challenge for the scientific community.  Use of magnetic materials to build computing devices like memories and processors has emerged as a promising avenue for creating “beyond-CMOS” computers,
     

Propelling atomically layered magnets toward green computers

Globally, computation is booming at an unprecedented rate, fueled by the boons of artificial intelligence. With this, the staggering energy demand of the world’s computing infrastructure has become a major concern, and the development of computing devices that are far more energy-efficient is a leading challenge for the scientific community. 

Use of magnetic materials to build computing devices like memories and processors has emerged as a promising avenue for creating “beyond-CMOS” computers, which would use far less energy compared to traditional computers. Magnetization switching in magnets can be used in computation the same way that a transistor switches from open or closed to represent the 0s and 1s of binary code. 

While much of the research along this direction has focused on using bulk magnetic materials, a new class of magnetic materials — called two-dimensional van der Waals magnets — provides superior properties that can improve the scalability and energy efficiency of magnetic devices to make them commercially viable. 

Although the benefits of shifting to 2D magnetic materials are evident, their practical induction into computers has been hindered by some fundamental challenges. Until recently, 2D magnetic materials could operate only at very low temperatures, much like superconductors. So bringing their operating temperatures above room temperature has remained a primary goal. Additionally, for use in computers, it is important that they can be controlled electrically, without the need for magnetic fields. Bridging this fundamental gap, where 2D magnetic materials can be electrically switched above room temperature without any magnetic fields, could potentially catapult the translation of 2D magnets into the next generation of “green” computers.

A team of MIT researchers has now achieved this critical milestone by designing a “van der Waals atomically layered heterostructure” device where a 2D van der Waals magnet, iron gallium telluride, is interfaced with another 2D material, tungsten ditelluride. In an open-access paper published March 15 in Science Advances, the team shows that the magnet can be toggled between the 0 and 1 states simply by applying pulses of electrical current across their two-layer device. 

“Our device enables robust magnetization switching without the need for an external magnetic field, opening up unprecedented opportunities for ultra-low power and environmentally sustainable computing technology for big data and AI,” says lead author Deblina Sarkar, the AT&T Career Development Assistant Professor at the MIT Media Lab and Center for Neurobiological Engineering, and head of the Nano-Cybernetic Biotrek research group. “Moreover, the atomically layered structure of our device provides unique capabilities including improved interface and possibilities of gate voltage tunability, as well as flexible and transparent spintronic technologies.”

Sarkar is joined on the paper by first author Shivam Kajale, a graduate student in Sarkar’s research group at the Media Lab; Thanh Nguyen, a graduate student in the Department of Nuclear Science and Engineering (NSE); Nguyen Tuan Hung, an MIT visiting scholar in NSE and an assistant professor at Tohoku University in Japan; and Mingda Li, associate professor of NSE.

Breaking the mirror symmetries 

When electric current flows through heavy metals like platinum or tantalum, the electrons get segregated in the materials based on their spin component, a phenomenon called the spin Hall effect, says Kajale. The way this segregation happens depends on the material, and particularly its symmetries.

“The conversion of electric current to spin currents in heavy metals lies at the heart of controlling magnets electrically,” Kajale notes. “The microscopic structure of conventionally used materials, like platinum, have a kind of mirror symmetry, which restricts the spin currents only to in-plane spin polarization.”

Kajale explains that two mirror symmetries must be broken to produce an “out-of-plane” spin component that can be transferred to a magnetic layer to induce field-free switching. “Electrical current can 'break' the mirror symmetry along one plane in platinum, but its crystal structure prevents the mirror symmetry from being broken in a second plane.”

In their earlier experiments, the researchers used a small magnetic field to break the second mirror plane. To get rid of the need for a magnetic nudge, Kajale and Sarkar and colleagues looked instead for a material with a structure that could break the second mirror plane without outside help. This led them to another 2D material, tungsten ditelluride. The tungsten ditelluride that the researchers used has an orthorhombic crystal structure. The material itself has one broken mirror plane. Thus, by applying current along its low-symmetry axis (parallel to the broken mirror plane), the resulting spin current has an out-of-plane spin component that can directly induce switching in the ultra-thin magnet interfaced with the tungsten ditelluride. 

“Because it's also a 2D van der Waals material, it can also ensure that when we stack the two materials together, we get pristine interfaces and a good flow of electron spins between the materials,” says Kajale. 

Becoming more energy-efficient 

Computer memory and processors built from magnetic materials use less energy than traditional silicon-based devices. And the van der Waals magnets can offer higher energy efficiency and better scalability compared to bulk magnetic material, the researchers note. 

The electrical current density used for switching the magnet translates to how much energy is dissipated during switching. A lower density means a much more energy-efficient material. “The new design has one of the lowest current densities in van der Waals magnetic materials,” Kajale says. “This new design has an order of magnitude lower in terms of the switching current required in bulk materials. This translates to something like two orders of magnitude improvement in energy efficiency.”

The research team is now looking at similar low-symmetry van der Waals materials to see if they can reduce current density even further. They are also hoping to collaborate with other researchers to find ways to manufacture the 2D magnetic switch devices at commercial scale. 

This work was carried out, in part, using the facilities at MIT.nano. It was funded by the Media Lab, the U.S. National Science Foundation, and the U.S. Department of Energy.

© Image courtesy of the researchers.

The flow of electrical current in the bottom crystalline slab (representing WTe2) breaks a mirror symmetry (shattered glass), while the material itself breaks the other mirror symmetry (cracked glass). The resulting spin current has vertical polarization that switches the magnetic state of the top 2D ferromagnet.

Creative collisions: Crossing the art-science divide

MIT has a rich history of productive collaboration between the arts and the sciences, anchored by the conviction that these two conventionally opposed ways of thinking can form a deeply generative symbiosis that serves to advance and humanize new technologies. 

This ethos was made tangible when the Bauhaus artist and educator György Kepes established the MIT Center for Advanced Visual Studies (CAVS) within the Department of Architecture in 1967. CAVS has since evolved into the Art, Culture, and Technology (ACT) program, which fosters close links to multiple other programs, centers, and labs at MIT. Class 4.373/4.374 (Creating Art, Thinking Science), open to undergraduates and master’s students of all disciplines as well as certain students from the Harvard Graduate School of Design (GSD), is one of the program’s most innovative offerings, proposing a model for how the relationship between art and science might play out at a time of exponential technological growth. 

Now in its third year, the class is supported by an Interdisciplinary Class Development Grant from the MIT Center for Art, Science and Technology (CAST) and draws upon the unparalleled resources of MIT.nano; an artist’s high-tech toolbox for investigating the hidden structures and beauty of our material universe.

High ambitions and critical thinking

The class was initiated by Tobias Putrih, lecturer in ACT, and is taught with the assistance of Ardalan SadeghiKivi MArch ’23, and Aubrie James SM ’24. Central to the success of the class has been the collaboration with co-instructor Vladimir Bulović, the founding director of MIT.nano and Fariborz Maseeh Chair in Emerging Technology, who has positioned the facility as an open-access resource for the campus at large — including MIT’s community of artists. “Creating Art, Thinking Science” unfolds the 100,000 square feet of cleanroom and lab space within the Lisa T. Su Building, inviting participating students to take advantage of cutting-edge equipment for nanoscale visualization and fabrication; in the hands of artists, devices for discovering nanostructures and manipulating atoms become tools for rendering the invisible visible and deconstructing the dynamics of perception itself. 

The expansive goals of the class are tempered by an in-built criticality. “ACT has a unique position as an art program nested within a huge scientific institute — and the challenges of that partnership should not be underestimated,” reflects Putrih. “Science and art are wholly different knowledge systems with distinct historical perspectives. So, how do we communicate? How do we locate that middle ground, that third space?”

An evolving answer, tested and developed throughout the partnership between ACT and MIT.nano, involves a combination of attentive mentorship and sharing of artistic ideas, combined with access to advanced technological resources and hands-on practical training. 

“MIT.nano currently accommodates more than 1,200 individuals to do their work, across 250 different research groups,” says Bulović. “The fact that we count artists among those is a matter of pride for us. We’ve found that the work of our scientists and technologists is enhanced by having access to the language of art as a form of expression — equally, the way that artists express themselves can be stretched beyond what could previously be imagined, simply by having access to the tools and instruments at MIT.nano.”

A playground for experimentation

True to the spirit of the scientific method and artistic iteration, the class is envisioned as a work in progress — a series of propositions and prototypes for how dialogue between scientists and artists might work in practice. The outcomes of those experiments can now be seen installed in the first and second floor galleries at MIT.nano. As part of the facility’s five-year anniversary celebration, the class premiered an exhibition showcasing works created during previous years of “Creating Art, Thinking Science.” 

Visitors to the exhibition, “zero.zerozerozerozerozerozerozerozeroone” (named for the numerical notation for one nanometer), will encounter artworks ranging from a minimalist silicon wafer produced with two-photon polymerization (2PP) technology (“Obscured Invisibility,” 2021, Hyun Woo Park), to traces of an attempt to make vegetable soup in the cleanroom using equipment such as a cryostat, a fluorescing microscope, and a Micro-CT scanner (“May I Please Make You Some Soup?,” 2022, Simone Lasser). 

These works set a precedent for the artworks produced during the fall 2023 iteration of the class. For Ryan Yang, in his senior year studying electrical engineering and computer science at MIT, the chance to engage in open discussion and experimental making has been a rare opportunity to “try something that might not work.” His project explores the possibilities of translating traditional block printing techniques to micron-scale 3D-printing in the MIT.nano labs.

Yang has taken advantage of the arts curriculum at MIT at an early stage in his academic career as an engineer; meanwhile, Ameen Kaleem started out as a filmmaker in New Delhi and is now pursuing a master’s degree in design engineering at Harvard GSD, cross-registered at MIT. 

Kaleem’s project models the process of abiogenesis (the evolution of living organisms from inorganic or inanimate substances) by bringing living moss into the MIT.nano cleanroom facilities to be examined at an atomic scale. “I was interested in the idea that, as a human being in the cleanroom, you are both the most sanitized version of yourself and the dirtiest thing in that space,” she reflects. “Drawing attention to the presence of organic life in the cleanroom is comparable to bringing art into spaces where it might not otherwise exist — a way of humanizing scientific and technological endeavors.”

Consciousness, immersion, and innovation

The students draw upon the legacies of landmark art-science initiatives — including international exhibitions such as “Cybernetic Serendipity” (London ICA, 1968), the “New Tendencies” series (Zagreb, 1961-73), and “Laboratorium” (Antwerp, 1999) — and take inspiration from the instructors’ own creative investigations of the inner workings of different knowledge systems. “In contemporary life, and at MIT in particular, we’re immersed in technology,” says Putrih. “It’s the nature of art to reveal that to us, so that we might see the implications of what we are producing and its potential impact.”

By fostering a mindset of imagination and criticality, combined with building the technical skills to address practical problems, “Creating Art, Thinking Science” seeks to create the conditions for a more expansive version of technological optimism; a culture of innovation in which social and environmental responsibility are seen as productive parameters for enriched creativity. The ripple effects of the class might be years in the making, but as Bulović observes while navigating the exhibition at MIT.nano, “The joy of the collaboration can be felt in the artworks.”

© Photo courtesy of MIT CAST.

Two students engage with an artwork created in 4.373/4.374 (Creating Art, Thinking Science).

Researchers harness 2D magnetic materials for energy-efficient computing

Experimental computer memories and processors built from magnetic materials use far less energy than traditional silicon-based devices. Two-dimensional magnetic materials, composed of layers that are only a few atoms thick, have incredible properties that could allow magnetic-based devices to achieve unprecedented speed, efficiency, and scalability.

While many hurdles must be overcome until these so-called van der Waals magnetic materials can be integrated into functioning computers, MIT researchers took an important step in this direction by demonstrating precise control of a van der Waals magnet at room temperature.

This is key, since magnets composed of atomically thin van der Waals materials can typically only be controlled at extremely cold temperatures, making them difficult to deploy outside a laboratory.

The researchers used pulses of electrical current to switch the direction of the device’s magnetization at room temperature. Magnetic switching can be used in computation, the same way a transistor switches between open and closed to represent 0s and 1s in binary code, or in computer memory, where switching enables data storage.

The team fired bursts of electrons at a magnet made of a new material that can sustain its magnetism at higher temperatures. The experiment leveraged a fundamental property of electrons known as spin, which makes the electrons behave like tiny magnets. By manipulating the spin of electrons that strike the device, the researchers can switch its magnetization.

“The heterostructure device we have developed requires an order of magnitude lower electrical current to switch the van der Waals magnet, compared to that required for bulk magnetic devices,” says Deblina Sarkar, the AT&T Career Development Assistant Professor in the MIT Media Lab and Center for Neurobiological Engineering, head of the Nano-Cybernetic Biotrek Lab, and the senior author of a paper on this technique. “Our device is also more energy efficient than other van der Waals magnets that are unable to switch at room temperature.”

In the future, such a magnet could be used to build faster computers that consume less electricity. It could also enable magnetic computer memories that are nonvolatile, which means they don’t leak information when powered off, or processors that make complex AI algorithms more energy-efficient.

“There is a lot of inertia around trying to improve materials that worked well in the past. But we have shown that if you make radical changes, starting by rethinking the materials you are using, you can potentially get much better solutions,” says Shivam Kajale, a graduate student in Sarkar’s lab and co-lead author of the paper.

Kajale and Sarkar are joined on the paper by co-lead author Thanh Nguyen, a graduate student in the Department of Nuclear Science and Engineering (NSE); Corson Chao, a graduate student in the Department of Materials Science and Engineering (DSME); David Bono, a DSME research scientist; Artittaya Boonkird, an NSE graduate student; and Mingda Li, associate professor of nuclear science and engineering. The research appears this week in Nature Communications.

An atomically thin advantage

Methods to fabricate tiny computer chips in a clean room from bulk materials like silicon can hamper devices. For instance, the layers of material may be barely 1 nanometer thick, so minuscule rough spots on the surface can be severe enough to degrade performance.

By contrast, van der Waals magnetic materials are intrinsically layered and structured in such a way that the surface remains perfectly smooth, even as researchers peel off layers to make thinner devices. In addition, atoms in one layer won’t leak into other layers, enabling the materials to retain their unique properties when stacked in devices.

“In terms of scaling and making these magnetic devices competitive for commercial applications, van der Waals materials are the way to go,” Kajale says.

But there’s a catch. This new class of magnetic materials have typically only been operated at temperatures below 60 kelvins (-351 degrees Fahrenheit). To build a magnetic computer processor or memory, researchers need to use electrical current to operate the magnet at room temperature.

To achieve this, the team focused on an emerging material called iron gallium telluride. This atomically thin material has all the properties needed for effective room temperature magnetism and doesn’t contain rare earth elements, which are undesirable because extracting them is especially destructive to the environment.

Nguyen carefully grew bulk crystals of this 2D material using a special technique. Then, Kajale fabricated a two-layer magnetic device using nanoscale flakes of iron gallium telluride underneath a six-nanometer layer of platinum.

Tiny device in hand, they used an intrinsic property of electrons known as spin to switch its magnetization at room temperature.

Electron ping-pong

While electrons don’t technically “spin” like a top, they do possess the same kind of angular momentum. That spin has a direction, either up or down. The researchers can leverage a property known as spin-orbit coupling to control the spins of electrons they fire at the magnet.

The same way momentum is transferred when one ball hits another, electrons will transfer their “spin momentum” to the 2D magnetic material when they strike it. Depending on the direction of their spins, that momentum transfer can reverse the magnetization.

In a sense, this transfer rotates the magnetization from up to down (or vice-versa), so it is called a “torque,” as in spin-orbit torque switching. Applying a negative electric pulse causes the magnetization to go downward, while a positive pulse causes it to go upward.

The researchers can do this switching at room temperature for two reasons: the special properties of iron gallium telluride and the fact that their technique uses small amounts of electrical current. Pumping too much current into the device would cause it to overheat and demagnetize.

The team faced many challenges over the two years it took to achieve this milestone, Kajale says. Finding the right magnetic material was only half the battle. Since iron gallium telluride oxidizes quickly, fabrication must be done inside a glovebox filled with nitrogen.

“The device is only exposed to air for 10 or 15 seconds, but even after that I have to do a step where I polish it to remove any oxide,” he says.

Now that they have demonstrated room-temperature switching and greater energy efficiency, the researchers plan to keep pushing the performance of magnetic van der Waals materials.

“Our next milestone is to achieve switching without the need for any external magnetic fields. Our aim is to enhance our technology and scale up to bring the versatility of van der Waals magnet to commercial applications,” Sarkar says.

This work was carried out, in part, using the facilities at MIT.Nano and the Harvard University Center for Nanoscale Systems.

© Image: Courtesy of the researchers

This illustration shows electric current being pumped into platinum (the bottom slab), which results in the creation of an electron spin current that switches the magnetic state of the 2D ferromagnet on top. The colored spheres represent the atoms in the 2D material.

Researchers harness 2D magnetic materials for energy-efficient computing

Experimental computer memories and processors built from magnetic materials use far less energy than traditional silicon-based devices. Two-dimensional magnetic materials, composed of layers that are only a few atoms thick, have incredible properties that could allow magnetic-based devices to achieve unprecedented speed, efficiency, and scalability.

While many hurdles must be overcome until these so-called van der Waals magnetic materials can be integrated into functioning computers, MIT researchers took an important step in this direction by demonstrating precise control of a van der Waals magnet at room temperature.

This is key, since magnets composed of atomically thin van der Waals materials can typically only be controlled at extremely cold temperatures, making them difficult to deploy outside a laboratory.

The researchers used pulses of electrical current to switch the direction of the device’s magnetization at room temperature. Magnetic switching can be used in computation, the same way a transistor switches between open and closed to represent 0s and 1s in binary code, or in computer memory, where switching enables data storage.

The team fired bursts of electrons at a magnet made of a new material that can sustain its magnetism at higher temperatures. The experiment leveraged a fundamental property of electrons known as spin, which makes the electrons behave like tiny magnets. By manipulating the spin of electrons that strike the device, the researchers can switch its magnetization.

“The heterostructure device we have developed requires an order of magnitude lower electrical current to switch the van der Waals magnet, compared to that required for bulk magnetic devices,” says Deblina Sarkar, the AT&T Career Development Assistant Professor in the MIT Media Lab and Center for Neurobiological Engineering, head of the Nano-Cybernetic Biotrek Lab, and the senior author of a paper on this technique. “Our device is also more energy efficient than other van der Waals magnets that are unable to switch at room temperature.”

In the future, such a magnet could be used to build faster computers that consume less electricity. It could also enable magnetic computer memories that are nonvolatile, which means they don’t leak information when powered off, or processors that make complex AI algorithms more energy-efficient.

“There is a lot of inertia around trying to improve materials that worked well in the past. But we have shown that if you make radical changes, starting by rethinking the materials you are using, you can potentially get much better solutions,” says Shivam Kajale, a graduate student in Sarkar’s lab and co-lead author of the paper.

Kajale and Sarkar are joined on the paper by co-lead author Thanh Nguyen, a graduate student in the Department of Nuclear Science and Engineering (NSE); Corson Chao, a graduate student in the Department of Materials Science and Engineering (DSME); David Bono, a DSME research scientist; Artittaya Boonkird, an NSE graduate student; and Mingda Li, associate professor of nuclear science and engineering. The research appears this week in Nature Communications.

An atomically thin advantage

Methods to fabricate tiny computer chips in a clean room from bulk materials like silicon can hamper devices. For instance, the layers of material may be barely 1 nanometer thick, so minuscule rough spots on the surface can be severe enough to degrade performance.

By contrast, van der Waals magnetic materials are intrinsically layered and structured in such a way that the surface remains perfectly smooth, even as researchers peel off layers to make thinner devices. In addition, atoms in one layer won’t leak into other layers, enabling the materials to retain their unique properties when stacked in devices.

“In terms of scaling and making these magnetic devices competitive for commercial applications, van der Waals materials are the way to go,” Kajale says.

But there’s a catch. This new class of magnetic materials have typically only been operated at temperatures below 60 kelvins (-351 degrees Fahrenheit). To build a magnetic computer processor or memory, researchers need to use electrical current to operate the magnet at room temperature.

To achieve this, the team focused on an emerging material called iron gallium telluride. This atomically thin material has all the properties needed for effective room temperature magnetism and doesn’t contain rare earth elements, which are undesirable because extracting them is especially destructive to the environment.

Nguyen carefully grew bulk crystals of this 2D material using a special technique. Then, Kajale fabricated a two-layer magnetic device using nanoscale flakes of iron gallium telluride underneath a six-nanometer layer of platinum.

Tiny device in hand, they used an intrinsic property of electrons known as spin to switch its magnetization at room temperature.

Electron ping-pong

While electrons don’t technically “spin” like a top, they do possess the same kind of angular momentum. That spin has a direction, either up or down. The researchers can leverage a property known as spin-orbit coupling to control the spins of electrons they fire at the magnet.

The same way momentum is transferred when one ball hits another, electrons will transfer their “spin momentum” to the 2D magnetic material when they strike it. Depending on the direction of their spins, that momentum transfer can reverse the magnetization.

In a sense, this transfer rotates the magnetization from up to down (or vice-versa), so it is called a “torque,” as in spin-orbit torque switching. Applying a negative electric pulse causes the magnetization to go downward, while a positive pulse causes it to go upward.

The researchers can do this switching at room temperature for two reasons: the special properties of iron gallium telluride and the fact that their technique uses small amounts of electrical current. Pumping too much current into the device would cause it to overheat and demagnetize.

The team faced many challenges over the two years it took to achieve this milestone, Kajale says. Finding the right magnetic material was only half the battle. Since iron gallium telluride oxidizes quickly, fabrication must be done inside a glovebox filled with nitrogen.

“The device is only exposed to air for 10 or 15 seconds, but even after that I have to do a step where I polish it to remove any oxide,” he says.

Now that they have demonstrated room-temperature switching and greater energy efficiency, the researchers plan to keep pushing the performance of magnetic van der Waals materials.

“Our next milestone is to achieve switching without the need for any external magnetic fields. Our aim is to enhance our technology and scale up to bring the versatility of van der Waals magnet to commercial applications,” Sarkar says.

This work was carried out, in part, using the facilities at MIT.Nano and the Harvard University Center for Nanoscale Systems.

© Image: Courtesy of the researchers

This illustration shows electric current being pumped into platinum (the bottom slab), which results in the creation of an electron spin current that switches the magnetic state of the 2D ferromagnet on top. The colored spheres represent the atoms in the 2D material.

Researchers harness 2D magnetic materials for energy-efficient computing

Experimental computer memories and processors built from magnetic materials use far less energy than traditional silicon-based devices. Two-dimensional magnetic materials, composed of layers that are only a few atoms thick, have incredible properties that could allow magnetic-based devices to achieve unprecedented speed, efficiency, and scalability.

While many hurdles must be overcome until these so-called van der Waals magnetic materials can be integrated into functioning computers, MIT researchers took an important step in this direction by demonstrating precise control of a van der Waals magnet at room temperature.

This is key, since magnets composed of atomically thin van der Waals materials can typically only be controlled at extremely cold temperatures, making them difficult to deploy outside a laboratory.

The researchers used pulses of electrical current to switch the direction of the device’s magnetization at room temperature. Magnetic switching can be used in computation, the same way a transistor switches between open and closed to represent 0s and 1s in binary code, or in computer memory, where switching enables data storage.

The team fired bursts of electrons at a magnet made of a new material that can sustain its magnetism at higher temperatures. The experiment leveraged a fundamental property of electrons known as spin, which makes the electrons behave like tiny magnets. By manipulating the spin of electrons that strike the device, the researchers can switch its magnetization.

“The heterostructure device we have developed requires an order of magnitude lower electrical current to switch the van der Waals magnet, compared to that required for bulk magnetic devices,” says Deblina Sarkar, the AT&T Career Development Assistant Professor in the MIT Media Lab and Center for Neurobiological Engineering, head of the Nano-Cybernetic Biotrek Lab, and the senior author of a paper on this technique. “Our device is also more energy efficient than other van der Waals magnets that are unable to switch at room temperature.”

In the future, such a magnet could be used to build faster computers that consume less electricity. It could also enable magnetic computer memories that are nonvolatile, which means they don’t leak information when powered off, or processors that make complex AI algorithms more energy-efficient.

“There is a lot of inertia around trying to improve materials that worked well in the past. But we have shown that if you make radical changes, starting by rethinking the materials you are using, you can potentially get much better solutions,” says Shivam Kajale, a graduate student in Sarkar’s lab and co-lead author of the paper.

Kajale and Sarkar are joined on the paper by co-lead author Thanh Nguyen, a graduate student in the Department of Nuclear Science and Engineering (NSE); Corson Chao, a graduate student in the Department of Materials Science and Engineering (DSME); David Bono, a DSME research scientist; Artittaya Boonkird, an NSE graduate student; and Mingda Li, associate professor of nuclear science and engineering. The research appears this week in Nature Communications.

An atomically thin advantage

Methods to fabricate tiny computer chips in a clean room from bulk materials like silicon can hamper devices. For instance, the layers of material may be barely 1 nanometer thick, so minuscule rough spots on the surface can be severe enough to degrade performance.

By contrast, van der Waals magnetic materials are intrinsically layered and structured in such a way that the surface remains perfectly smooth, even as researchers peel off layers to make thinner devices. In addition, atoms in one layer won’t leak into other layers, enabling the materials to retain their unique properties when stacked in devices.

“In terms of scaling and making these magnetic devices competitive for commercial applications, van der Waals materials are the way to go,” Kajale says.

But there’s a catch. This new class of magnetic materials have typically only been operated at temperatures below 60 kelvins (-351 degrees Fahrenheit). To build a magnetic computer processor or memory, researchers need to use electrical current to operate the magnet at room temperature.

To achieve this, the team focused on an emerging material called iron gallium telluride. This atomically thin material has all the properties needed for effective room temperature magnetism and doesn’t contain rare earth elements, which are undesirable because extracting them is especially destructive to the environment.

Nguyen carefully grew bulk crystals of this 2D material using a special technique. Then, Kajale fabricated a two-layer magnetic device using nanoscale flakes of iron gallium telluride underneath a six-nanometer layer of platinum.

Tiny device in hand, they used an intrinsic property of electrons known as spin to switch its magnetization at room temperature.

Electron ping-pong

While electrons don’t technically “spin” like a top, they do possess the same kind of angular momentum. That spin has a direction, either up or down. The researchers can leverage a property known as spin-orbit coupling to control the spins of electrons they fire at the magnet.

The same way momentum is transferred when one ball hits another, electrons will transfer their “spin momentum” to the 2D magnetic material when they strike it. Depending on the direction of their spins, that momentum transfer can reverse the magnetization.

In a sense, this transfer rotates the magnetization from up to down (or vice-versa), so it is called a “torque,” as in spin-orbit torque switching. Applying a negative electric pulse causes the magnetization to go downward, while a positive pulse causes it to go upward.

The researchers can do this switching at room temperature for two reasons: the special properties of iron gallium telluride and the fact that their technique uses small amounts of electrical current. Pumping too much current into the device would cause it to overheat and demagnetize.

The team faced many challenges over the two years it took to achieve this milestone, Kajale says. Finding the right magnetic material was only half the battle. Since iron gallium telluride oxidizes quickly, fabrication must be done inside a glovebox filled with nitrogen.

“The device is only exposed to air for 10 or 15 seconds, but even after that I have to do a step where I polish it to remove any oxide,” he says.

Now that they have demonstrated room-temperature switching and greater energy efficiency, the researchers plan to keep pushing the performance of magnetic van der Waals materials.

“Our next milestone is to achieve switching without the need for any external magnetic fields. Our aim is to enhance our technology and scale up to bring the versatility of van der Waals magnet to commercial applications,” Sarkar says.

This work was carried out, in part, using the facilities at MIT.Nano and the Harvard University Center for Nanoscale Systems.

© Image: Courtesy of the researchers

This illustration shows electric current being pumped into platinum (the bottom slab), which results in the creation of an electron spin current that switches the magnetic state of the 2D ferromagnet on top. The colored spheres represent the atoms in the 2D material.

Researchers harness 2D magnetic materials for energy-efficient computing

Experimental computer memories and processors built from magnetic materials use far less energy than traditional silicon-based devices. Two-dimensional magnetic materials, composed of layers that are only a few atoms thick, have incredible properties that could allow magnetic-based devices to achieve unprecedented speed, efficiency, and scalability.

While many hurdles must be overcome until these so-called van der Waals magnetic materials can be integrated into functioning computers, MIT researchers took an important step in this direction by demonstrating precise control of a van der Waals magnet at room temperature.

This is key, since magnets composed of atomically thin van der Waals materials can typically only be controlled at extremely cold temperatures, making them difficult to deploy outside a laboratory.

The researchers used pulses of electrical current to switch the direction of the device’s magnetization at room temperature. Magnetic switching can be used in computation, the same way a transistor switches between open and closed to represent 0s and 1s in binary code, or in computer memory, where switching enables data storage.

The team fired bursts of electrons at a magnet made of a new material that can sustain its magnetism at higher temperatures. The experiment leveraged a fundamental property of electrons known as spin, which makes the electrons behave like tiny magnets. By manipulating the spin of electrons that strike the device, the researchers can switch its magnetization.

“The heterostructure device we have developed requires an order of magnitude lower electrical current to switch the van der Waals magnet, compared to that required for bulk magnetic devices,” says Deblina Sarkar, the AT&T Career Development Assistant Professor in the MIT Media Lab and Center for Neurobiological Engineering, head of the Nano-Cybernetic Biotrek Lab, and the senior author of a paper on this technique. “Our device is also more energy efficient than other van der Waals magnets that are unable to switch at room temperature.”

In the future, such a magnet could be used to build faster computers that consume less electricity. It could also enable magnetic computer memories that are nonvolatile, which means they don’t leak information when powered off, or processors that make complex AI algorithms more energy-efficient.

“There is a lot of inertia around trying to improve materials that worked well in the past. But we have shown that if you make radical changes, starting by rethinking the materials you are using, you can potentially get much better solutions,” says Shivam Kajale, a graduate student in Sarkar’s lab and co-lead author of the paper.

Kajale and Sarkar are joined on the paper by co-lead author Thanh Nguyen, a graduate student in the Department of Nuclear Science and Engineering (NSE); Corson Chao, a graduate student in the Department of Materials Science and Engineering (DSME); David Bono, a DSME research scientist; Artittaya Boonkird, an NSE graduate student; and Mingda Li, associate professor of nuclear science and engineering. The research appears this week in Nature Communications.

An atomically thin advantage

Methods to fabricate tiny computer chips in a clean room from bulk materials like silicon can hamper devices. For instance, the layers of material may be barely 1 nanometer thick, so minuscule rough spots on the surface can be severe enough to degrade performance.

By contrast, van der Waals magnetic materials are intrinsically layered and structured in such a way that the surface remains perfectly smooth, even as researchers peel off layers to make thinner devices. In addition, atoms in one layer won’t leak into other layers, enabling the materials to retain their unique properties when stacked in devices.

“In terms of scaling and making these magnetic devices competitive for commercial applications, van der Waals materials are the way to go,” Kajale says.

But there’s a catch. This new class of magnetic materials have typically only been operated at temperatures below 60 kelvins (-351 degrees Fahrenheit). To build a magnetic computer processor or memory, researchers need to use electrical current to operate the magnet at room temperature.

To achieve this, the team focused on an emerging material called iron gallium telluride. This atomically thin material has all the properties needed for effective room temperature magnetism and doesn’t contain rare earth elements, which are undesirable because extracting them is especially destructive to the environment.

Nguyen carefully grew bulk crystals of this 2D material using a special technique. Then, Kajale fabricated a two-layer magnetic device using nanoscale flakes of iron gallium telluride underneath a six-nanometer layer of platinum.

Tiny device in hand, they used an intrinsic property of electrons known as spin to switch its magnetization at room temperature.

Electron ping-pong

While electrons don’t technically “spin” like a top, they do possess the same kind of angular momentum. That spin has a direction, either up or down. The researchers can leverage a property known as spin-orbit coupling to control the spins of electrons they fire at the magnet.

The same way momentum is transferred when one ball hits another, electrons will transfer their “spin momentum” to the 2D magnetic material when they strike it. Depending on the direction of their spins, that momentum transfer can reverse the magnetization.

In a sense, this transfer rotates the magnetization from up to down (or vice-versa), so it is called a “torque,” as in spin-orbit torque switching. Applying a negative electric pulse causes the magnetization to go downward, while a positive pulse causes it to go upward.

The researchers can do this switching at room temperature for two reasons: the special properties of iron gallium telluride and the fact that their technique uses small amounts of electrical current. Pumping too much current into the device would cause it to overheat and demagnetize.

The team faced many challenges over the two years it took to achieve this milestone, Kajale says. Finding the right magnetic material was only half the battle. Since iron gallium telluride oxidizes quickly, fabrication must be done inside a glovebox filled with nitrogen.

“The device is only exposed to air for 10 or 15 seconds, but even after that I have to do a step where I polish it to remove any oxide,” he says.

Now that they have demonstrated room-temperature switching and greater energy efficiency, the researchers plan to keep pushing the performance of magnetic van der Waals materials.

“Our next milestone is to achieve switching without the need for any external magnetic fields. Our aim is to enhance our technology and scale up to bring the versatility of van der Waals magnet to commercial applications,” Sarkar says.

This work was carried out, in part, using the facilities at MIT.Nano and the Harvard University Center for Nanoscale Systems.

© Image: Courtesy of the researchers

This illustration shows electric current being pumped into platinum (the bottom slab), which results in the creation of an electron spin current that switches the magnetic state of the 2D ferromagnet on top. The colored spheres represent the atoms in the 2D material.
  • ✇Latest
  • How Third-World Countries Build Walkable Cities Without Central PlanningScott Beyer
    Jakarta, Indonesia—The central business district of Indonesia's 11 million-person capital has the social contrast found in many other developing world megacities. Modern skyscrapers accommodate Indonesia's elite, while shabby informal villages spread from the base of such buildings. I wanted to experience this latter, more common, style so one morning my translator Julya and I walked a few minutes from my upscale French hotel chain across a dirty
     

How Third-World Countries Build Walkable Cities Without Central Planning

18. Únor 2024 v 13:00
A corridor in a dense Indonesian 'superblock' | Photos by Scott Beyer

Jakarta, Indonesia—The central business district of Indonesia's 11 million-person capital has the social contrast found in many other developing world megacities. Modern skyscrapers accommodate Indonesia's elite, while shabby informal villages spread from the base of such buildings. I wanted to experience this latter, more common, style so one morning my translator Julya and I walked a few minutes from my upscale French hotel chain across a dirty canal and into a village.

The standardized First World planning aesthetic of square buildings and engineered roadways quickly yielded to clustered huts organized along a twisty network of alleys. This village style is common in the Third World, a bastion of organic, market-oriented development that often withstands the modernization plans of city officials, even in central areas. It bears a striking resemblance to a popular concept in the Western urban planning world: the "superblock."

In superblocks, wide roads and streets are spaced far apart rather than allocated frequently on a grid pattern. The area in between, too condensed to accommodate cars, is reserved for pedestrians, motorbikes, buildings, and courtyards, with alleyways connecting it all.

Such blocks were the historical default before cities were planned for automobiles and before machines made clearing rights of way much easier. Paths would extend along routes that were topographically easy and would be cleared just wide enough for needed pass-throughs.

European villages with their hilly outdoor staircases fit the superblock stereotype, but the style has even deeper roots in Asia, with the oldest known example in China. In their contribution to the book Governing Cities: Asia's Urban Transformation, scholars Daixin Dai and George R. Frantz describe the ones planned in 1036 B.Cfor the ancient city of Chengzhou. The pattern persisted through the millennia; 1400s Beijing, according to urbanNext, consisted of "blocks of houses on 150-meter hutong nested in 1,000-meter superblocks," themselves found in larger structures called "megablocks."

Superblocks were common in the colonial and industrial-era U.S., with Philadelphia, for example, growing into a maze of tight alleyways for horse carriages. Savannah, Georgia, was planned for superblocks—still partially intact today—and there are still scattered examples throughout the Northeast and Midwest.

Modern planners increasingly recognize the benefits of superblocks and want to bring them back. Cutting off large residential segments of the city to cars reduces traffic deaths, air pollution, and other negative externalities. The idea has been proposed in Los Angeles, where the City Council hopes to implement a pilot superblock in the city center, and in Seattle, where one is proposed for the Capitol Hill neighborhood.

Urban planners tend to be progressives, and superblock promoters think their idea will be achieved through government planning. The most successful First World superblock retrofit was pushed through that way, in Barcelona. There, the government prohibited automobile traffic through several thoroughfares in the 2010s, allowing pedestrians to move through freely; the authorities hope to create 500 such blocks. Beyond just alleys, a number of blocks have shops, courtyards, and parks.

The effort caused car storage in one Barcelona neighborhood to fall 82 percent. The change has plenty of fans: The World Health Organization reports that in one converted district, residents experienced "a perceived gain in well-being, tranquility and quality of sleep." And it was clearly a government project. As David Roberts wrote in Vox almost five years ago, Barcelona "has always been an intentional city, closely conceived and constructed by central planners." Unsurprisingly, it was planners, in turn, who undid the city's grid and instilled superblocks.

But across the developing world, the opposite is true. In Africa, Asia, and Latin America, superblocks remain the de facto market-driven development pattern, for much the same reasons they were in the ancient world. Most of the population doesn't own cars and is not in an economic position to afford more space. So they maximize the space they have, causing superblock shantytowns to pop up on hillsides, farmland, or even infill urban areas that are being illegally "invaded." The poorer the area, the more devoid it will be of setback requirements, parking minimums, and similar regulations—and the likelier it will be to yield the superblock vernacular.

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We got a sense of the economic reasons why when walking through the Jakarta village, called Kebon Jahe. This is one of central Jakarta's many urban villages—a neighborhood format known to locals as perkampungan. Kebon Jahe literally is a superblock, in that the entire boundary is one big block of a dozen or so square acres, flanked by big arterial roads but with no significant through roads.

We entered the village wanting to learn how it got planned (or unplanned) to look this way. Julya, a native to the Jakarta area, knew we must first talk to the neighborhood chief.

After veering down one alley and asking around, we were taken down an even smaller alley and introduced to Budi Aprianto. A middle-aged man, he is one of 15 village chiefs, all democratically elected by the block's roughly 1,500 residents.

Kebon Jahe, he explained, was colonized in the 1700s by the Dutch, who built a cemetery there. When Indonesians got back control of the land during the 1940s revolution, the area was converted into farmland and a livestock market. The buildings that exist now began rising in the 1970s, to accompany population demands in central Jakarta. The village has not grown through the efforts of a master developer. A collection of families, many of them in the area for generations, had erected their own homes.

How, I asked, did a sophisticated alley network get built in such a decentralized growth system? After I paid a small bribe, he agreed to show me around.

The network, he explained, is as coordinated as it looks, forming a U shape that lets residents access the whole village. But there are three right-of-way categories.

The first consists of the relatively wide roads that form the entry of Kebon Jahe before hitting up against alleys. These were built by the government, allow cars to park (haphazardly), and have formal retail, such as the popular Alfamart chain.

The second, and primary, form of right of way is the alleys. They're 6 feet to 12 feet wide, meaning they can only handle pedestrians and motorbikes, and they accommodate most of the retail, with merchants setting up stores along or even into the alley. The government paves them and manages them for safety and clearance, but they follow a market logic. They began as private clearances for farmers who were seeking the easiest transport path. Development grew along them, and only later did the government take over. This is why they zigzag along land curves rather than fitting the straight lines common in a grid.

Third are the extremely narrow alleys that veer off these main ones. These are still private. Any given acre in Kebon Jahe has hundreds of small houses so scrunched together it's hard to tell them apart. Most homes don't front the street but, in a pattern atypical in even America's densest cities, go deep into the lot—meaning almost every last square foot of land is covered.

The only parts not covered are the alleys, which allow inside-outside access for these further-back houses. The alleys are also places for hanging birdcages, drying laundry, and running small commercial stands. They're created through negotiation between homeowners, all of whom benefit from the access. But they're extremely narrow—I had to turn sideways while walking through some—and that just boils down to economics.

"Jakarta is a very crowded city," Aprianto explained through my translator. "People use every bit of space they can for themselves."

Some of the extremely narrow alleys actually began as the wider formal public ones. But when adjacent homeowners want to expand their dwellings, they build additions into the alley, unintentionally similar to the invasive favela-style growth seen in Brazil. These households leave just enough alley space that they themselves can get out.

While building onto public alleys is illegal, enforcement is loose, given that Kebon Jahe is a mostly self-governing slum. (Aprianto is an elected leader, but he is not a government official.) In the rare cases when city inspectors appear, residents just pay them off.


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Before visiting Kebon Jahe, Julya and I explored some superblocks in Tangerang, the working-class Jakarta suburb where she grew up. Many more exist there—unsurprisingly, given that it's an industrial city where factory workers need places to live. Tangerang superblocks are often centered around small mosques (Indonesia is the country with the world's largest Islamic population) or around dirty canals that nonetheless meet certain economic needs.

The same order can be found across the Global South: Large factories are built on city outskirts and quickly get surrounded by informal slums, virtually all of which adopt some variation of the superblock layout. Again, this is not because people there share the ideals of Western planners. Nor do these superblocks have the bells and whistles of the Spanish ones. It's simply the most logical layout in societies defined by economic and spatial scarcity.

Superblocks are more vulnerable in central areas, thanks to pressure to wipe them out and build to higher-end uses. That is not usually a market process. As our Kebon Jahe tour was ending, we passed the more formal area at the village exit, which had a wider alley and larger buildings.

"By next year, all of Kebon Jahe might look like this," Aprianto said.

The city has already started harassing the village's street merchants, and it's planning a program to raze Kebon Jahe homes and replace them with towers. Residents will receive payments from the government that, while large to them, won't be enough to buy replacement units in central Jakarta. Instead, they must find comparably priced units further out, meaning they're effectively being displaced through eminent domain. Such slum clearance is common across the Global South, as it once was in the United States.

It might surprise America's professional planners to hear it, but governments don't usually create superblocks—they destroy them.

The post How Third-World Countries Build Walkable Cities Without Central Planning appeared first on Reason.com.

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