Faces of MIT: Lydia Brosnahan

A lot of behind-the-scenes work goes into creating an art installation or a theater production – not just by those making or performing their craft, but also by the staff members who coordinate the logistics of exhibits and events. One of the people at MIT who helps artists bring their projects to life is Lydia Brosnahan.  

In her role as associate producer in the Office of the Arts, Brosnahan works with several different arts initiatives including the MIT Center for Art, Science and Technology (CAST) and the Council for the Arts at MIT (CAMIT).  

“The arts at MIT are alive and well,” says Brosnahan, who has worked at the Institute for six years. “My job involves administering grants to faculty for their own artistic work as well as visiting artist residency projects where faculty members invite an artist to campus to collaborate with them, their students, and with the MIT community. Every visiting artist residency has some sort of public component, which could be an event or an activity.” 

It’s a collaborative effort in the Office of the Arts and the tasks of the department do not end with grant selection, distribution, and event execution. Brosnahan’s colleagues are also involved in student art programs, with running the MIT Arts Studios classes, and with the Wiesner Student Art Gallery, which features exhibitions of artwork by MIT students.  

“I also coordinate the CAMIT grants program, which primarily supports artistic projects by students,” Brosnahan explains. “Right now, for example, there is an exhibition in the Wiesner Student Art Gallery that was supported by a grant from CAMIT. 

“When I tell people outside of the Institute that I work in the arts at MIT they usually respond with, ‘There are arts programs at MIT?’ I think that is kind of the general impression. Outside of our visiting artists programs, we also have public art collections, architecture...there are so many student artists who are doing it as part of their career or to enhance their degree. There are theater groups who put on productions and organizations that take part in music and dance. I want people to know that the arts here are rich and amazing.” 

One of the projects Brosnahan is most proud to have worked in was part of a collaboration between CAST and the MIT Museum. “The first collaborative project that we did, that I got to help launch, was an exhibition called Arachnodrone. It's an installation that is based on research about spiderwebs and is a collaboration between engineers in civil and environmental engineering, researchers, and musicians who took the vibrational frequency of spiderwebs and turned it into music. It is both an installation and a performance.”

She also enjoys producing Arts on the Radar, a big kick-off celebration in the first week of September. “It is basically a way to say 'The arts are here. Come check them out!' We have demonstrations by students and collaborate with other arts units on campus including the List Visual Arts Center; the Art, Culture, and Technology program; the Department of Architecture; the Morningside Academy for Design; and Music and Theater Arts. We come together to throw a big party with the goal of helping people learn about what opportunities are available in the arts. It’s fun!”

Soundbytes

Q: What do you like the most about your job? 

Brosnahan: The people. Every project I work on is a little bit different because everyone who comes to us has a cool idea for a project. There is never a dull moment! Often there are projects that bring together art, science, and technology in new ways. I learn a lot just from being around interesting people and projects. 

Q: If someone was about to start working in MIT, what advice would you give them? 

Brosnahan: Wander around campus. Get lost, explore, and try to meet people from every corner of MIT. When you start working here, there is a rush of new things to learn. It’s beneficial, and just great, to learn about everything going on here. I still find myself walking around, getting lost on campus, and discovering a different research lab I didn’t know about.  

Q: Are you involved in any groups or clubs offered to staff members outside of your job? 

Brosnahan: I'm a big fan of, and participant in, the MIT Language Conversation Exchange. LCE holds language lunches where you can sit at a specific language table and practice speaking that language with language learners and native speakers. They also have a program where you get matched with partners of MIT students, staff, and faculty as a one-on-one conversation partner. You note what language(s) you speak, which you want to learn, and then you can see if someone speaks one you want to learn. I'm really into foreign languages and I was excited to learn about that opportunity and get involved in the wider community.

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MIT engineers 3D print the electromagnets at the heart of many electronics

Imagine being able to build an entire dialysis machine using nothing more than a 3D printer.

This could not only reduce costs and eliminate manufacturing waste, but since this machine could be produced outside a factory, people with limited resources or those who live in remote areas may be able to access this medical device more easily.

While multiple hurdles must be overcome to develop electronic devices that are entirely 3D printed, a team at MIT has taken an important step in this direction by demonstrating fully 3D-printed, three-dimensional solenoids.

Solenoids, electromagnets formed by a coil of wire wrapped around a magnetic core, are a fundamental building block of many electronics, from dialysis machines and respirators to washing machines and dishwashers.

The researchers modified a multimaterial 3D printer so it could print compact, magnetic-cored solenoids in one step. This eliminates defects that might be introduced during post-assembly processes.

This customized printer, which could utilize higher-performing materials than typical commercial printers, enabled the researchers to produce solenoids that could withstand twice as much electric current and generate a magnetic field that was three times larger than other 3D-printed devices.

In addition to making electronics cheaper on Earth, this printing hardware could be particularly useful in space exploration. For example, instead of shipping replacement electronic parts to a base on Mars, which could take years and cost millions of dollars, one could send a signal containing files for the 3D printer, says Luis Fernando Velásquez-García, a principal research scientist in MIT’s Microsystems Technology Laboratories (MTL).

“There is no reason to make capable hardware in only a few centers of manufacturing when the need is global. Instead of trying to ship hardware all over the world, can we empower people in distant places to make it themselves? Additive manufacturing can play a tremendous role in terms of democratizing these technologies,” adds Velásquez-García, the senior author of a new paper on the 3D printed solenoids that appears in the journal Virtual and Physical Prototyping.

He is joined on the paper by lead author Jorge Cañada, an electrical engineering and computer science graduate student; and Hyeonseok Kim, a mechanical engineering graduate student.

Additive advantages

A solenoid generates a magnetic field when an electrical current is passed through it. When someone rings a doorbell, for instance, electric current flows through a solenoid, which generates a magnetic field that moves an iron rod so it strikes a chime.

Integrating solenoids onto electrical circuits manufactured in a clean room poses significant challenges, as they have very different form factors and are made using incompatible processes that require post assembly. Consequently, researchers have investigated making solenoids utilizing many of the same processes that make semiconductor chips. But these techniques limit the size and shape of solenoids, which hampers performance.

With additive manufacturing, one can produce devices that are practically any size and shape. However, this presents its own challenges, since making a solenoid involves coiling thin layers made from multiple materials that may not all be compatible with one machine.

To overcome these challenges, the researchers needed to modify a commercial extrusion 3D printer.

Extrusion printing fabricates objects one layer at a time by squirting material through a nozzle. Typically, a printer uses one type of material feedstock, often spools of filament.

“Some people in the field look down on them because they are simple and don’t have a lot of bells and whistles, but extrusion is one of very few methods that allows you to do multimaterial, monolithic printing,” says Velásquez-García.

This is key, since the solenoids are produced by precisely layering three different materials — a dielectric material that serves as an insulator, a conductive material that forms the electric coil, and a soft magnetic material that makes up the core.

The team selected a printer with four nozzles — one dedicated to each material to prevent cross-contamination. They needed four extruders because they tried two soft magnetic materials, one based on a biodegradable thermoplastic and the other based on nylon.

Printing with pellets

They retrofitted the printer so one nozzle could extrude pellets, rather than filament. The soft magnetic nylon, which is made from a pliable polymer studded with metallic microparticles, is virtually impossible to produce as a filament. Yet this nylon material offers far better performance than filament-based alternatives.

Using the conductive material also posed challenges, since it would start melting and jam the nozzle. The researchers found that adding ventilation to cool the material prevented this. They also built a new spool holder for the conductive filament that was closer to the nozzle, reducing friction that could damage the thin strands.

Even with the team’s modifications, the customized hardware cost about $4,000, so this technique could be employed by others at a lower cost than other approaches, adds Velásquez-García.

The modified hardware prints a U.S. quarter-sized solenoid as a spiral by layering material around the soft magnetic core, with thicker conductive layers separated by thin insulating layers.

Precisely controlling the process is of paramount importance because each material prints at a different temperature. Depositing one on top of another at the wrong time might cause the materials to smear.

Because their machine could print with a more effective soft magnetic material, the solenoids achieved higher performance than other 3D-printed devices.

The printing method enabled them to build a three-dimensional device comprising eight layers, with coils of conductive and insulating material stacked around the core like a spiral staircase. Multiple layers increase the number of coils in the solenoid, which improves the amplification of the magnetic field.

Due to the added precision of the modified printer, they could make solenoids that were about 33 percent smaller than other 3D-printed versions. More coils in a smaller area also boosts amplification.

In the end, their solenoids could produce a magnetic field that was about three times larger than what other 3D-printed devices can achieve.

“We were not the first people to be able to make inductors that are 3D-printed, but we were the first ones to make them three-dimensional, and that greatly amplifies the kinds of values you can generate. And that translates into being able to satisfy a wider range of applications,” he says.

For instance, while these solenoids can’t generate as much magnetic field as those made with traditional fabrication techniques, they could be used as power convertors in small sensors or actuators in soft robots.

Moving forward, the researchers are looking to continue enhancing their performance.

For one, they could try using alternate materials that might have better properties. They are also exploring additional modifications that could more precisely control the temperature at which each material is deposited, reducing defects.

This work is funded by Empiriko Corporation.

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Nourishing the mind, hand, and stomach

As early as middle school, Branden Spitzer loved to watch cooking shows and experiment with recipes in his family’s kitchen. It was a clear harbinger of his interest in materials science, he says now. Once he discovered that he could delight others with a perfectly executed pie, he began to see the many ways that his passion for baking might branch into other areas requiring technical acuity.

“We have this deep connection to food, the things that we wear, the products around us that we experience or work with every day,” says the MIT senior. “I hope we can make those things even better using science and engineering.”

Spitzer is a materials science and engineering major and has rounded out his education by cross registering for food science classes at Harvard University. He has pursued a variety of research opportunities related to food and sustainability, from extending the shelf-life of produce to developing lab-grown meat.

Spitzer also sees food as a means of social nourishment. He enjoys exploring restaurants and having dinners with friends, and takes special pleasure in planning and putting together meals. “I love making pies and cooking because you can share something with people that they think is really tasty,” he says. “And by eating the food they can understand all the thought and everything that went into it. I want the work or research I go on to do to have that same sort of tangible impact.”

Sampling a huge menu

Upon beginning his first year at MIT, Spitzer was overwhelmed by the seemingly endless amount of activities the Institute had to offer. He says the busy student culture was one of the things that attracted him to MIT, yet once he was face-to-face with it all, he didn’t know where to begin. He recalls one of his first-year advisors instructing him to “ride the wave,” and he took this to heart. Open to trying anything, Spitzer set forth on several academic and extracurricular journeys that would lead him in completely different directions through his four years.

He pursued research projects centered on food and sustainability. In one of his first research positions, Spitzer worked for Mori, a Cambridge-based startup that makes a silk-based coating that slows the spoiling of fruits and vegetables. His longest-running research project, in Professor Markus Buehler’s Laboratory for Atomistic and Molecular Mechanics, involves working with mycelium, the root systems of mushrooms, to improve and alter the growth of the material for use in 3D printing. He spent a summer interning for a company in South Africa that is working on a lab-grown meat product, and currently he is interning for Faerm, a plant-based cheese company in Copenhagen, Denmark. He hopes to continue this in this direction after graduation, either at a startup or in graduate school studying materials science or biological engineering.

Spitzer also strives to make a positive impact on his local community at MIT through his work. He participated in activities ranging from physical education to the arts, and everything in between. He joined the student organization MCG, the MIT Consulting Group, solving real-world business problems for clients. Spitzer is also a member of the Phi Delta Theta fraternity, where he served as vice president for three semesters and introduced an initiative to prioritize inclusivity and mental health awareness. And, he joined MIT’s lighting design group, which he says exposed him to new entirely new communities of artists and engineers.  

Spitzer has been fond of traveling since he was a child. He recalls taking trips with his family often, visiting historical and global landmarks. In the past four years he has embarked on multiple study abroad and work experiences through MISTI and is enthusiastic about the unexpected places his internships have taken him. He has spent time in the U.K., Brazil, and South Africa, and will be studying in Denmark this semester.

In Brazil, Spitzer helped to develop and teach a materials science program and class. He says it was exciting to share the subjects of polymers, recycling, and sustainability with students in a different part of the world. In South Africa, Spitzer interned for the Mzansi Meat Co. (now Newform Foods), which he came across by surprise after searching for companies that were making cultured meat products.

Pirates at MIT

Spurred by MIT’s physical education requirements, Spitzer has found a passion for several sports activities. Sailing, for example, has become one of his favorite hobbies. “It’s super cool that we have a chance to do these crazy things,” he says when referring to his time spent taking out sailboats to practice for his sailing class on the Charles River.

Sailing is one of four physical education classes needed to obtain the MIT Pirate Certificate, an incentive that encourages participation in MIT’s P.E. offerings. Spitzer pursued this achievement, enrolling in archery, rifle, and fencing classes over several semesters. The diverse course selection allowed for unexpected discoveries. “I was surprised and blown away by how much the rifle practice was an exercise in thought, focus, and meditation,” he says. “It was very different than I expected, in a very pleasant way.”

Ice skating is another discovery Spitzer made through his four required gym classes. He has taken many more classes by now though since they are “super fun.” Beginning as a nervous newcomer with no experience, Spitzer now takes an intermediate skating class where he develops his skills in turns and speed skating.

Spitzer also enjoys recreational cycling and indoor rock climbing in his spare time, as well as yoga and dancing. He has taken multiple dance classes in his time at MIT and has been a member of the organization MIT DanceTroupe for four years.

Whether in the kitchen, lab, or gym, Spitzer has found a robust community in all corners of the MIT campus and beyond. Rather than choosing one area of focus, Spitzer states the most integral aspect of his student experience at MIT was getting a taste for everything: “You just try things out here. You learn the things you love or the things you hate, and get to do something really cool along the way.”

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MLK Celebration Gala pays tribute to Martin Luther King Jr. and his writings on “the goal of true education”

After a week of festivities around campus, members of the MIT community gathered Saturday evening in the Boston Marriott Kendall Square ballroom to celebrate the life and legacy of Martin Luther King Jr. Marking 50 years of this annual celebration at MIT, the gala event’s program was loosely organized around a line in King’s essay, “The Purpose of Education,” which he penned as an undergraduate at Morehouse College:

“We must remember that intelligence is not enough,” King wrote. “Intelligence plus character — that is the goal of true education.”

Senior Myles Noel was the master of ceremonies for the evening and welcomed one and all. Minister DiOnetta Jones Crayton, former director of the Office of Minority Education and associate dean of minority education, delivered the invocation, exhorting the audience to embrace “the fiery urgency of now.” Next, MIT President Sally Kornbluth shared her remarks.

She acknowledged that at many institutions, diversity and inclusion efforts are eroding. Kornbluth reiterated her commitment to these efforts, saying, “I want to be clear about how important I believe it is to keep such efforts strong — and to make them the best they can be. The truth is, by any measure, MIT has never been more diverse, and it has never been more excellent. And we intend to keep it that way.”

Kornbluth also recognized the late Paul Parravano, co-director of MIT’s Office of Government and Community Relations, who was a staff member at MIT for 33 years as well as the longest-serving member on the MLK Celebration Committee. Parravano’s “long and distinguished devotion to the values and goals of Dr. Martin Luther King, Jr. inspires us all,” Kornbluth said, presenting his family with the 50th Anniversary Lifetime Achievement Award. 

Next, students and staff shared personal reflections. Zina Queen, office manager in the Department of Political Science, noted that her family has been a part of the MIT community for generations. Her grandmother, Rita, her mother, Wanda, and her daughter have all worked or are currently working at the Institute. Queen pointed out that her family epitomizes another of King’s oft-repeated quotes, “Every man is an heir to a legacy of dignity and worth.”

Senior Tamea Cobb noted that MIT graduates have a particular power in the world that they must use strategically and with intention. “Education and service go hand and hand,” she said, adding that she intends “every one of my technical abilities will be used to pursue a career that is fulfilling, expansive, impactful, and good.”

Graduate student Austin K. Cole ’24 addressed the Israel-Hamas conflict and the MIT administration. As he spoke, some attendees left their seats to stand with Cole at the podium. Cole closed his remarks with a plea to resist state and structural violence, and instead focus on relationship and mutuality.

After dinner, incoming vice president for equity and inclusion Karl Reid ’84, SM ’85 honored Adjunct Professor Emeritus Clarence Williams for his distinguished service to the Institute. Williams was an assistant to three MIT presidents, served as director of the Office of Minority Education, taught in the Department of Urban Planning, initiated the MIT Black History Project, and mentored hundreds of students. Reid was one of those students, and he shared a few of his mentor’s oft repeated phrases:

“Do the work and let the talking take care of itself.”

“Bad ideas kill themselves; great ideas flourish.”

In closing, Reid exhorted the audience to create more leaders who, like Williams, embody excellence and mutual respect for others.

The keynote address was given by civil rights activist Janet Moses, a member of the Student Nonviolent Coordinating Committee (SNCC) in the 1960s; a physician who worked for a time as a pediatrician at MIT Health; a longtime resident of Cambridge, Massachusetts; and a co-founder, with her husband, Robert Moses, of the Algebra Project, a pioneering program grounded in the belief “that in the 21st century every child has a civil right to secure math literacy — the ability to read, write, and reason with the symbol systems of mathematics.”

A striking image of a huge new building planned for New York City appeared on the screen behind Moses during her address. It was a rendering of a new jail being built at an estimated cost of $3 billion. Against this background, she described the trajectory of the “carceral state,” which began in 1771 with the Mansfield Judgement in England. At the time, “not even South Africa had a set of race laws as detailed as those in the U.S.,” Moses observed.

Today, the carceral state uses all levels of government to maintain a racial caste system that is deeply entrenched, Moses argued, drawing a connection between the purported need for a new prison complex and a statistic that Black people in New York state are three times more likely than whites to be convicted for a crime.

She referenced a McKinsey study that it will take Black people over three centuries to achieve a quality of life on parity with whites. Despite the enormity of this challenge, Moses encouraged the audience to “rock the boat and churn the waters of the status quo.” She also pointed out that “there is joy in the struggle.”

Symbols of joy were also on display at the Gala in the forms of original visual art and poetry, and a quilt whose squares were contributed by MIT staff, students, and alumni, hailing from across the Institute.

Quilts are a physical manifestation of the legacy of the enslaved in America and their descendants — the ability to take scraps and leftovers to create something both practical and beautiful. The 50th anniversary quilt also incorporated a line from King’s highly influential “I Have a Dream Speech”:

“One day, all God’s children will have the riches of freedom and the security of justice.”

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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.

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Thirty-five outstanding MIT students selected as Burchard Scholars for 2024

MIT’s School of Humanities, Arts, and Social Sciences (SHASS) has announced that 35 MIT undergraduate sophomores and juniors have been named Burchard Scholars for 2024.

Elected by the Burchard Committee from a large pool of impressive applicants, all students chosen for the program have demonstrated excellence and engagement in the humanistic fields, but can major in science, design, and engineering fields as well as the humanities, arts, and social sciences.

In the course of this calendar year, the Burchard Scholars will attend seminar dinners with members of the SHASS faculty, during which they will have the chance to engage with the faculty and one another. The program is designed to both broaden horizons for promising students and provide scholars the chance to engage in friendly but challenging discussions in which to hone skills for expressing, critiquing, and debating ideas with peers and mentors.

During the course of the calendar year, the scholars also attend several cultural events in the Boston metropolitan area.

The key features of these dinners are presentations by SHASS’ faculty, on topics ranging from nuclear security to an economic view of artificial intelligence to cross-cultural histories in centuries-old manuscripts. Drawing on the school’s vast and varied fields of expertise, the seminars offer near-endless avenues of exploration for ambitious scholars.

It is perhaps no surprise that a high percentage of the MIT students who receive Rhodes, Marshall, and other major scholarships and fellowships are former Burchard Scholars. “These students are an extraordinary group of MIT undergraduates," says Margery Resnick, associate professor of literature and director of the Burchard program. “They are thoughtful, smart, and enthusiastic about the opportunity to discuss a wide range of ideas with faculty and fellow students.”

The 2024 Burchard Scholars, their academic years, and majors are:

• Mustafa Al-Obaidi, junior, mechanical engineering;
• Saul Balcarcel-Salazar, junior, physics;
• Miguel Buitrago, sophomore, philosophy;
• Julia Camacho, junior, urban studies and planning;
• Kaelyn Dunnell, junior, literature;
• Isabella Gandara, junior, biological engineering;
• Renee Ge, junior, electrical engineering and computer science;
• Graham Guite, sophomore, biological engineering;
• Janka Hamori, junior, electrical engineering and computer science;
• Vivian Hir, junior, electrical engineering and computer science;
• Sashko Horokh, junior, mathematics;
• Janvi Huria, junior, electrical engineering and computer science;
• Emily Kang, junior, electrical engineering and computer science;
• Kelly Kim, sophomore, literature;
• Esther Kinyanjui, junior, electrical engineering and computer science;
• Alice Le, junior, writing;
• Rumi Lee, junior, electrical engineering and computer science;
• Effaima Longe, junior, chemistry;
• Tarang Lunawat, junior, electrical engineering and computer science;
• Ariel McGee, sophomore, writing;
• Leena Mehendale, sophomore, biological engineering;
• Zev Moore, sophomore, management;
• Franklin Nguyen, junior, electrical engineering and computer science;
• Mishael Quraishi, junior, materials science and engineering;
• Syd Robinson, junior, materials science and engineering;
• James Rock, sophomore, political science;
• Katie Spivakovsky, sophomore, Biological Engineering;
• Mohamed Suufi, junior, electrical engineering and computer science;
• Alex Tang, sophomore, biology;
• Margaret Wang, junior, mathematics;
• Ashley Williams, junior, electrical engineering and computer science;
• Felicia Xiao, junior, physics;
• Kaitlyn Yanna, junior, nuclear science and engineering;
• Elizabeth Zhang, sophomore, electrical engineering and computer science; and
• Grace Zhang, junior, mathematics.

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Electrons become fractions of themselves in graphene, study finds

The electron is the basic unit of electricity, as it carries a single negative charge. This is what we’re taught in high school physics, and it is overwhelmingly the case in most materials in nature.

But in very special states of matter, electrons can splinter into fractions of their whole. This phenomenon, known as “fractional charge,” is exceedingly rare, and if it can be corralled and controlled, the exotic electronic state could help to build resilient, fault-tolerant quantum computers.

To date, this effect, known to physicists as the “fractional quantum Hall effect,” has been observed a handful of times, and mostly under very high, carefully maintained magnetic fields. Only recently have scientists seen the effect in a material that did not require such powerful magnetic manipulation.

Now, MIT physicists have observed the elusive fractional charge effect, this time in a simpler material: five layers of graphene — an atom-thin layer of carbon that stems from graphite and common pencil lead. They report their results today in Nature.

They found that when five sheets of graphene are stacked like steps on a staircase, the resulting structure inherently provides just the right conditions for electrons to pass through as fractions of their total charge, with no need for any external magnetic field.

The results are the first evidence of the “fractional quantum anomalous Hall effect” (the term “anomalous” refers to the absence of a magnetic field) in crystalline graphene, a material that physicists did not expect to exhibit this effect.

“This five-layer graphene is a material system where many good surprises happen,” says study author Long Ju, assistant professor of physics at MIT. “Fractional charge is just so exotic, and now we can realize this effect with a much simpler system and without a magnetic field. That in itself is important for fundamental physics. And it could enable the possibility for a type of quantum computing that is more robust against perturbation.”

Ju’s MIT co-authors are lead author Zhengguang Lu, Tonghang Han, Yuxuan Yao, Aidan Reddy, Jixiang Yang, Junseok Seo, and Liang Fu, along with Kenji Watanabe and Takashi Taniguchi at the National Institute for Materials Science in Japan.

A bizarre state

The fractional quantum Hall effect is an example of the weird phenomena that can arise when particles shift from behaving as individual units to acting together as a whole. This collective “correlated” behavior emerges in special states, for instance when electrons are slowed from their normally frenetic pace to a crawl that enables the particles to sense each other and interact. These interactions can produce rare electronic states, such as the seemingly unorthodox splitting of an electron’s charge.

In 1982, scientists discovered the fractional quantum Hall effect in heterostructures of gallium arsenide, where a gas of electrons confined in a two-dimensional plane is placed under high magnetic fields. The discovery later won the group a Nobel Prize in Physics.

“[The discovery] was a very big deal, because these unit charges interacting in a way to give something like fractional charge was very, very bizarre,” Ju says. “At the time, there were no theory predictions, and the experiments surprised everyone.”

Those researchers achieved their groundbreaking results using magnetic fields to slow down the material’s electrons enough for them to interact. The fields they worked with were about 10 times stronger than what typically powers an MRI machine.

In August 2023, scientists at the University of Washington reported the first evidence of fractional charge without a magnetic field. They observed this “anomalous” version of the effect, in a twisted semiconductor called molybdenum ditelluride. The group prepared the material in a specific configuration, which theorists predicted would give the material an inherent magnetic field, enough to encourage electrons to fractionalize without any external magnetic control.

The “no magnets” result opened a promising route to topological quantum computing — a more secure form of quantum computing, in which the added ingredient of topology (a property that remains unchanged in the face of weak deformation or disturbance) gives a qubit added protection when carrying out a computation. This computation scheme is based on a combination of fractional quantum Hall effect and a superconductor. It used to be almost impossible to realize: One needs a strong magnetic field to get fractional charge, while the same magnetic field will usually kill the superconductor. In this case the fractional charges would serve as a qubit (the basic unit of a quantum computer).

Making steps

That same month, Ju and his team happened to also observe signs of anomalous fractional charge in graphene — a material for which there had been no predictions for exhibiting such an effect.

Ju’s group has been exploring electronic behavior in graphene, which by itself has exhibited exceptional properties. Most recently, Ju’s group has looked into pentalayer graphene — a structure of five graphene sheets, each stacked slightly off from the other, like steps on a staircase. Such pentalayer graphene structure is embedded in graphite and can be obtained by exfoliation using Scotch tape. When placed in a refrigerator at ultracold temperatures, the structure’s electrons slow to a crawl and interact in ways they normally wouldn’t when whizzing around at higher temperatures.

In their new work, the researchers did some calculations and found that electrons might interact with each other even more strongly if the pentalayer structure were aligned with hexagonal boron nitride (hBN) — a material that has a similar atomic structure to that of graphene, but with slightly different dimensions. In combination, the two materials should produce a moiré superlattice — an intricate, scaffold-like atomic structure that could slow electrons down in ways that mimic a magnetic field.

“We did these calculations, then thought, let’s go for it,” says Ju, who happened to install a new dilution refrigerator in his MIT lab last summer, which the team planned to use to cool materials down to ultralow temperatures, to study exotic electronic behavior.

The researchers fabricated two samples of the hybrid graphene structure by first exfoliating graphene layers from a block of graphite, then using optical tools to identify five-layered flakes in the steplike configuration. They then stamped the graphene flake onto an hBN flake and placed a second hBN flake over the graphene structure. Finally, they attached electrodes to the structure and placed it in the refrigerator, set to near absolute zero.

As they applied a current to the material and measured the voltage output, they started to see signatures of fractional charge, where the voltage equals the current multiplied by a fractional number and some fundamental physics constants.

“The day we saw it, we didn’t recognize it at first,” says first author Lu. “Then we started to shout as we realized, this was really big. It was a completely surprising moment.”

“This was probably the first serious samples we put in the new fridge,” adds co-first author Han. “Once we calmed down, we looked in detail to make sure that what we were seeing was real.”

With further analysis, the team confirmed that the graphene structure indeed exhibited the fractional quantum anomalous Hall effect. It is the first time the effect has been seen in graphene.

“Graphene can also be a superconductor,” Ju says. “So, you could have two totally different effects in the same material, right next to each other. If you use graphene to talk to graphene, it avoids a lot of unwanted effects when bridging graphene with other materials.”

For now, the group is continuing to explore multilayer graphene for other rare electronic states.

“We are diving in to explore many fundamental physics ideas and applications,” he says. “We know there will be more to come.”

This research is supported in part by the Sloan Foundation, and the National Science Foundation.

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