MIT Confirms Unconventional Superconductivity in MATTG

Superconductivity occurs when electrons pair up, rather than scattering apart as they do in normal conductors or in everyday materials. These paired electrons are called “Cooper pairs,’ which creates a perfect, resistance-free flow of current.

This remarkable property is observed in superconductors when they are cooled below a specific “critical temperature.” Besides allowing a current to flow indefinitely without energy loss, these materials also expel magnetic fields, which enables them to levitate.

While conventional superconductors, such as those made of aluminium, require very low temperatures, researchers are actively developing materials that can superconduct at higher, more practical temperatures, a step that could revolutionize energy and quantum technologies.

Researchers at MIT have now achieved this breakthrough. They have observed a distinctive V-shaped energy gap, which points to unconventional superconductivity in magic-angle graphene, marking an important advance toward room-temperature superconductors.

Magic-Angle Graphene & ‘Twistronics’: How Layer Rotation Changes Physics

Ever since the discovery of “magic-angle” graphene, it has created a lot of buzz in the scientific world, with researchers uncovering myriad exotic quantum phenomena ranging from correlated insulating states and unconventional superconductivity to tunable magnetism and topological phases.

In 2018, a team of physicists at MIT, led by Pablo Jarillo-Herrero, first created and observed the effects of magic-angle graphene.

They detected unusual electronic properties, such as superconductivity, when two graphene layers are stacked at a very specific angle. That twisted structure is known as magic-angle twisted bilayer graphene, or MATBG.

Graphene is a single layer of carbon, which is just one atom thick and has a honeycomb lattice. The arrangement of carbon atoms in a hexagonal pattern resembles chicken wire and exhibits remarkable strength, durability, and the ability to conduct heat and electricity.

Bilayer graphene, meanwhile, is a stack of two layers in which the two lattices are oriented in a particular way. 

In pristine bilayer graphene, Jarillo-Herrero and his teammates observed Mott insulator behavior (a phenomenon in which a material becomes an insulator due to strong electron-electron repulsion, despite being expected to be a conductor) when the two layers were twisted at a magic angle.

This led to the development of “twistronics”, a promising new technique for adjusting the electronic properties of graphene by rotating adjacent layers of the material. 

The method was then used by a team of researchers from MIT, Harvard University, and NIMS in Japan to make the twisted bilayer superconducting by applying an electric field.

Over time, many researchers investigated various multilayer graphene structures, which showed signs of unconventional superconductivity.

Back in 2021, Harvard physicists successfully stacked three layers of graphene and twisted them at the magic angle to produce a three-layer system that exhibits robust superconductivity¹ at higher temperatures than many double-stacked graphene systems. Being sensitive to an externally applied electric field, it also allowed the team to tune superconductivity by adjusting the field’s strength.

This experiment helped scientists understand that the trilayer structure’s superconductivity is due to strong electron-electron interactions, which make it more resilient to higher temperatures. 

The same year, Princeton researchers reported an uncanny resemblance² between magic graphene’s superconductivity and that of high-temperature superconductors.

Using a scanning tunneling microscope (STM), they found that paired electrons have a finite angular momentum. The other concerned how the behavior of a superconducting material changes when the superconducting state is quenched by increasing the temperature or applying a magnetic field. While electrons unpair in conventional superconductors, in unconventional ones, some correlation is still retained.

MIT Forges Path to Room-Temperature Superconductors

The ability of superconductors to conduct electricity with zero resistance makes them key to technologies like MRI scanners, power transmission and storage, advanced computing, and particle accelerators.

But conventional superconductors only operate at very cold temperatures. So, they need to be kept in specialized cooling systems to help them maintain their superconducting state.

If these materials could superconduct at higher, more accessible temperatures, they could redefine technological systems worldwide. With this aim, scientists at MIT are investigating unconventional superconductors that depart from traditional behavior.

Recently, MIT physicists observed this phenomenon in “magic-angle” twisted tri-layer graphene (MATTG), providing direct confirmation that MATTG can host unconventional superconductivity³.

As Jeong Min Park, the co-lead author of the study, noted, in conventional superconductors, the electrons in ‘Cooper pairs’ are very far away from each other, and weakly bound, unlike in magic-angle graphene, where “we could already see signatures that these pairs are very tightly bound, almost like a molecule. There were hints that there was something very different about this material.”

While previous studies provided clues, it wasn’t precisely confirmed. As the study noted, understanding the nature of superconductivity in magic-angle graphene has been challenging, with the main difficulty being in discerning the superconducting gap. 

The MIT team, however, successfully measured MATTG’s superconducting gap, revealing the strength of its superconducting state at different temperatures. What they found was a gap in MATTG that was entirely different from that in conventional superconductors, suggesting that MATTG’s becoming superconducting depends on an unusual mechanism.
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As the study’s co-lead author, Shuwen Sun, a graduate student in MIT’s Department of Physics, noted, there isn’t one but many different mechanisms that can lead to superconductivity in materials, and it is the superconducting gap that provides a hint as to which particular mechanism leads to room-temperature superconductors to revolutionize energy and technology.

“When a material becomes superconducting, electrons move together as pairs rather than individually, and there’s an energy gap that reflects how they’re bound. The shape and symmetry of that gap tells us the underlying nature of the superconductivity.”

– Park

To prove their discovery of an unconventional mechanism, the team used a novel experimental system that allows them to directly observe how the superconducting gap forms in two-dimensional (2D) materials. 

For this, the researchers utilized tunneling spectroscopy. In this quantum-scale technique, electrons act as both waves and as particles, allowing them to “tunnel” through barriers that would normally stop them. By studying the ease with which electrons can tunnel through a material, researchers learn just how strongly they are bound inside it.

In this case, the team tunneled electrons between two layers of MATTG to measure its superconducting state.

This method alone, however, doesn’t always prove a material’s superconductivity, making direct measurement crucial yet challenging. So, the team combined tunneling spectroscopy with electrical transport measurements, which track how current moves through a material while monitoring its resistance.

The team used this approach on MATTG and clearly identified the superconducting tunneling gap, which appeared only when the material reached zero resistance.

Upon changing the temperature and magnetic field, this gap exhibited a sharp V-shaped curve rather than the smooth, flat pattern usually seen in conventional superconductors. As per the study, the unique low-energy superconducting gap vanishes at the superconducting critical temperature and magnetic field.

The distinct shape points to a new mechanism underlying MATTG’s superconductivity, which, while unknown, makes it clear that the material actually behaves differently from any conventional superconductor.

In most superconductors, electrons pair up due to vibrations in the surrounding atomic lattice, which push them together. But in MATTG, Park says, the pairing could be due to strong electronic interactions, which means “electrons themselves help each other pair up, forming a superconducting state with special symmetry.”

The technique that allowed the team to directly observe the superconducting gap, the combination of tunneling spectroscopy and transport measurements, will now be used to study various twisted and layered materials.

With the setup allowing the team to “identify and study the underlying electronic structures of superconductivity and other quantum phases as they happen, within the same sample,” Park noted that “this direct view can reveal how electrons pair and compete with other states, paving the way to design and control new superconductors and quantum materials that could one day power more efficient technologies or quantum computers.”

They will also use the experimental setup to study MATTG as well as other 2D materials in greater detail to find new, promising candidates for advanced technologies.

“Understanding one unconventional superconductor very well may trigger our understanding of the rest,” said the study’s senior author, Jarillo-Herrero, who’s the Cecil and Ida Green Professor of Physics at MIT. “This understanding may guide the design of superconductors that work at room temperature, for example, which is sort of the Holy Grail of the entire field.”

The Role of Quantum Geometry in Making Electrons Superfluid

While MIT’s latest discovery in magic-angle trilayer graphene marks a major leap toward understanding unconventional superconductivity, complementary studies are also helping fill in key details, such as how easily electron pairs flow through these materials.

It’s known that electrons in superconducting materials move with zero friction, but how easily electron pairs can flow depends on factors such as their density. The term “superfluid stiffness” describes how resistant a superconducting system is to changes in the flow of its electron pairs, making it a key indicator of superconductivity.

Earlier this year, physicists at MIT and Harvard University directly measured the superfluid stiffness in magic-angle graphene⁴ to better understand how the material superconducts. 

With this study, the aim has been to identify the mechanism responsible for superconductivity in magic-angle graphene, which is mainly determined by quantum geometry, or the conceptual ‘shape’ of quantum states in a material.

Now, to directly measure the superfluid stiffness, the team developed a new experimental technique that can also be used to make similar measurements of other 2D superconducting materials, of which “there’s a whole family… waiting to be probed.”

In materials like MATBG, the pairing of electrons, aka Cooper pairs, can form a superfluid, meaning they could move through a material as an effortless current. But while they have no resistance, some push still needs to be applied in the form of an electric field to get the current moving.

“Superfluid stiffness refers to how easy it is to get these particles to move, in order to drive superconductivity.“

– Study co-lead author Joel Wang, a research scientist in MIT’s Research Laboratory of Electronics (RLE)

This superfluid stiffness is usually measured using methods that place the superconducting material in a microwave resonator, a device that resonates at microwave frequencies. In a microwave resonator, the material modifies both the resonance frequency and kinetic inductance in proportion to its superfluid stiffness.

But these techniques have been compatible with samples only 10 to 100 times larger and thicker than MATBG, which means a new approach is needed to measure superfluid stiffness in atomically thin superconductors.

Now, the challenge with doing that with a supremely delicate material like MATBG is attaching it to the microwave resonator’s surface without disrupting its smoothness. This means, making “an ideally lossless — i.e., superconducting — contact between the two materials,” or the microwave signal sent will be degraded or just bounce back.

So, the team first assembled MATBG using standard fabrication techniques and then enclosed it between two insulating sheets of hexagonal boron nitride to preserve its delicate atomic structure and intrinsic properties.

The resonator was mostly aluminum, with a small amount of MATBG added to the end. To contact the MATBG, the team etched it very sharply, exposing a side of the newly cut MATBG, to which aluminum was deposited to “make a good contact and form an aluminum lead,” which was connected to the larger aluminum microwave resonator. 

The team sent a microwave signal through this resonator, measured the resulting shift in its resonance frequency, and deduced MATBG’s kinetic inductance. Upon converting the measured inductance to a value of superfluid stiffness, the team found it to be much larger than what conventional superconductivity theories would have predicted.

“We saw a tenfold increase in superfluid stiffness compared to conventional expectations, with a temperature dependence consistent with what the theory of quantum geometry predicts,” said co-lead author Miuko Tanaka. “This was a ‘smoking gun’ that pointed to the role of quantum geometry in governing superfluid stiffness in this two-dimensional material.“

Investing in Superconducting Tech

American Superconductor Corporation (AMSC -4.31%) is an energy technology company that manufactures advanced superconductor systems. It focuses on commercializing existing superconducting technologies and applying them to real-world power grid and naval applications.

AMSC is a leading provider of megawatt-scale power resiliency solutions, including Gridtec, Marinetec, and Windtec. 

Through these solutions, the company provides advanced grid systems to optimize network performance, efficiency, and reliability, propulsion and power management solutions to enhance power quality and operational safety, and wind turbine electronic controls and systems.

AMSC is a $1.66 billion market cap company, whose shares, as of writing, are trading at $36.97, up 49.86% YTD. Just last month, the share price had hit a peak of $70.49, but has fallen significantly since then. This massive 47.5% decline in less than a month has resulted from AMSC missing Wall Street sales targets.

Last week, the company reported its second-quarter fiscal 2025 revenue, which increased from $54.5 million in 2Q23 to $65.9 million. Its net income was $4.8 million, or $0.11 per share. As of September 30, 2025, AMSC had $218.8 million in cash, cash equivalents, and restricted cash, compared with $85.4 million at the end of March.

Talking about the 20% YoY growth in revenue, gross margins surpassing 30%, and generating nearly $5 million in net income to mark the fifth straight quarter of profitability, CEO Daniel P. McGahn said this was driven by “strong order demand across energy and military markets, supported by tailwinds in domestic manufacturing and reliable power needs across key sectors.”

For the third quarter, AMSC expects revenues to be in the range of $65 million to $70 million and net income to exceed $2 million, or $0.05 per share.

Latest American Superconductor Corporation (AMSC) Stock News

Conclusion

Superconductivity is one of the most transformative concepts in modern physics, with great influence on energy efficiency, computing, and materials science. The MIT team’s work with magic-angle twisted trilayer graphene (MATTG) represents a key advancement in uncovering how superconductivity can emerge through unconventional mechanisms.

These findings could also help us engineer materials that achieve superconductivity at room temperature, the long-sought “Holy Grail.” If realized, such materials could revolutionize everything from electric transportation to data centers and quantum computers, bringing a new era of technological possibility.

References

1. Hao, Z., Zimmerman, A. M., Ledwith, P., Khalaf, E., Haie Najafabadi, D., Watanabe, K., Taniguchi, T., Vishwanath, A. & Kim, P. Electric-field-tunable superconductivity in alternating-twist magic-angle trilayer graphene. Science 371, 1133–1138 (2021). https://doi.org/10.1126/science.abg0399
2. Oh, M., Nuckolls, K. P., Wong, D., Lee, R. L., Liu, X., Watanabe, K., Taniguchi, T. & Yazdani, A. Evidence for unconventional superconductivity in twisted bilayer graphene. Nature 600, 240–245 (2021). https://doi.org/10.1038/s41586-021-04121-x
3. Park, J. M., Sun, S., Watanabe, K., Taniguchi, T. & Jarillo-Herrero, P. Experimental evidence for nodal superconducting gap in moiré graphene. Science (2025). https://doi.org/10.1126/science.adv8376
4. Tanaka, M., Wang, J.έ-j., Dinh, T. H., Rodan-Legrain, D., Zaman, S., Hays, M., Almanakly, A., Kannan, B., Kim, D. K., Niedzielski, B. M., Serniak, K., Schwartz, M. E., Watanabe, K., Taniguchi, T., Orlando, T. P., Gustavsson, S., Grover, J. A., Jarillo-Herrero, P. & Oliver, W. D. Superfluid stiffness of magic-angle twisted bilayer graphene. Nature 638, 99–105 (2025). https://doi.org/10.1038/s41586-024-08494-7