Physicists use a new platform to measure magic-angle graphene’s superconducting gap. The method involves “tunneling” electrons between two layers of magic-angle twisted tri-layer graphene (in yellow) while measuring the material’s superconducting state. The team’s experiments are the first to show clear evidence that MATTG is an unconventional superconductor. Credit: Pablo Jarillo-Herrero, et al
MIT researchers uncovered clear evidence of unconventional superconductivity in magic-angle twisted trilayer graphene.
Their new measurement system revealed a sharp, V-shaped superconducting gap — proof of a new pairing mechanism unlike that in traditional superconductors. This breakthrough sheds light on quantum behaviors in ultra-thin materials and could accelerate the quest for room-temperature superconductivity.
Superconductors: Nature’s Perfect Conductors
Superconductors act like high-speed trains for electricity. When electric current enters one, it moves through effortlessly without losing energy. Because of this, superconductors are incredibly efficient and are already used in technologies such as MRI scanners and particle accelerators.
However, the superconductors used today have a major drawback: they only function at extremely low temperatures. To stay in their superconducting state, they must be cooled with complex, costly systems. If scientists could create materials that superconduct at warmer, near-room temperatures, the result could revolutionize technology—leading to energy grids and power lines with zero loss, and making quantum computers far more practical. Researchers at MIT and around the world are now focusing on “unconventional” superconductors, materials that behave differently from traditional ones and may hold the key to this next leap.
Magic-Angle Graphene Enters the Spotlight
MIT physicists have now announced compelling new evidence of unconventional superconductivity in “magic-angle” twisted tri-layer graphene (MATTG), a material built by stacking three ultrathin sheets of graphene at a precise angle. This subtle twist creates surprising electronic properties that cannot be found in ordinary materials.
Although earlier experiments had hinted at unusual superconductivity in MATTG, the new results, published in Science, provide the strongest proof yet that this material truly hosts an unconventional form of superconductivity.
Measuring the Superconducting Gap
The research team succeeded in measuring MATTG’s superconducting gap, a property that indicates how stable its superconducting state is at certain temperatures. What they observed was strikingly different from the pattern seen in typical superconductors, revealing that the way MATTG becomes superconducting follows a completely different, and unconventional, mechanism.
“There are many different mechanisms that can lead to superconductivity in materials,” says study co-lead author Shuwen Sun, a graduate student in MIT’s Department of Physics. “The superconducting gap gives us a clue to what kind of mechanism can lead to things like room-temperature superconductors that will eventually benefit human society.”
To make these observations, the researchers developed a new experimental setup that allows them to directly monitor how the superconducting gap forms in two-dimensional materials as it happens. They now plan to use this approach to study MATTG in greater detail and explore other 2D materials, hoping to identify new candidates that could one day transform energy and computing technologies.
The Holy Grail: Room-Temperature Superconductors
“Understanding one unconventional superconductor very well may trigger our understanding of the rest,” says Pablo Jarillo-Herrero, the Cecil and Ida Green Professor of Physics at MIT and the senior author of the study. “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 study’s other co-lead author is Jeong Min Park PhD ’24; Kenji Watanabe and Takashi Taniguchi of the National Institute for Materials Science in Japan are also co-authors.
The Ties That Bind: Twisting Graphene Into Magic
Graphene is a material that comprises a single layer of carbon atoms that are linked in a hexagonal pattern resembling chicken wire. A sheet of graphene can be isolated by carefully exfoliating an atom-thin flake from a block of graphite (the same stuff of pencil lead). In the 2010s, theorists predicted that if two graphene layers were stacked at a very special angle, the resulting structure should be capable of exotic electronic behavior.
In 2018, Jarillo-Herrero and his colleagues became the first to produce magic-angle graphene in experiments, and to observe some of its extraordinary properties. That discovery sprouted an entire new field known as “twistronics,” and the study of atomically thin, precisely twisted materials. Jarillo-Herrero’s group has since studied other configurations of magic-angle graphene with two, three, and more layers, as well as stacked and twisted structures of other two-dimensional materials. Their work, along with other groups, have revealed some signatures of unconventional superconductivity in some structures.
Cooper Pairs and the Dance of Electrons
Superconductivity is a state that a material can exhibit under certain conditions (usually at very low temperatures). When a material is a superconductor, any electrons that pass through can pair up, rather than repelling and scattering away. When they couple up in what is known as “Cooper pairs,” the electrons can glide through a material without friction, instead of knocking against each other and flying away as lost energy. This pairing up of electrons is what enables superconductivity, though the way in which they are bound can vary.
“In conventional superconductors, the electrons in these pairs are very far away from each other, and weakly bound,” says Park. “But in magic-angle graphene, we could already see signatures that these pairs are very tightly bound, almost like a molecule. There were hints that there is something very different about this material.”
Tunneling Through Quantum Walls
In their new study, Jarillo-Herrero and his colleagues aimed to directly observe and confirm unconventional superconductivity in a magic-angle graphene structure. To do so, they would have to measure the material’s superconducting gap.
“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,” Park explains. “The shape and symmetry of that gap tells us the underlying nature of the superconductivity.”
How Scientists Measure the Superconducting Gap
Scientists have measured the superconducting gap in materials using specialized techniques, such as tunneling spectroscopy. The technique takes advantage of a quantum mechanical property known as “tunneling.” At the quantum scale, an electron behaves not just as a particle, but also as a wave, and as such, its wave-like properties enable an electron to travel, or “tunnel” through a material, as if it could move through walls.
Such tunneling spectroscopy measurements can give an idea of how easy it is for an electron to tunnel into a material, and in some sense, how tightly packed and bound the electrons in the material are. When performed in a superconducting state, it can reflect the properties of the superconducting gap. However, tunneling spectroscopy alone cannot always tell whether the material is, in fact, in a superconducting state. Directly linking a tunneling signal to a genuine superconducting gap is both essential and experimentally challenging.
The Breakthrough: Watching the Gap Emerge
Park and her research team created a new experimental setup that links two powerful techniques: electron tunneling and electrical transport. The first allows scientists to probe the quantum behavior of electrons, while the second measures how easily current moves through a material. Together, these methods make it possible to test whether a material becomes superconducting by monitoring its electrical resistance in real time (zero resistance means the material has entered a superconducting state).
Using this combined platform, the researchers examined the superconducting gap in magic-angle twisted tri-layer graphene (MATTG). By recording both tunneling and transport data within the same device, they could clearly identify the superconducting tunneling gap, which appeared only when the material showed zero resistance, the unmistakable sign of superconductivity. They then studied how the gap changed under different temperatures and magnetic fields. The results revealed a sharp V-shaped pattern, unlike the flat, uniform gap typically found in conventional superconductors.
This unusual V-shaped signal suggests that electrons in MATTG pair up through a different, unconventional process. The exact cause of this pairing remains unknown, but the finding provides compelling proof that MATTG behaves as an unconventional superconductor.
Rethinking How Electrons Pair
In conventional superconductors, electrons form pairs through vibrations of the atomic lattice that surrounds them. These vibrations nudge the electrons together, allowing them to flow without resistance. Park and her team believe that something entirely different may be happening in MATTG.
“In this magic-angle graphene system, there are theories explaining that the pairing likely arises from strong electronic interactions rather than lattice vibrations,” she posits. “That means electrons themselves help each other pair up, forming a superconducting state with special symmetry.”
Toward a Future of Quantum Materials
Next, the researchers plan to use their experimental approach to explore other two-dimensional materials that are stacked or twisted in similar ways.
“This allows us to both identify and study the underlying electronic structures of superconductivity and other quantum phases as they happen, within the same sample,” Park says. “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.”
Reference: “Experimental evidence for nodal superconducting gap in moiré graphene” by Jeong Min Park, Shuwen Sun, Kenji Watanabe, Takashi Taniguchi and Pablo Jarillo-Herrero, 6 November 2025, Science.
This research was supported, in part, by the U.S. Army Research Office, the U.S. Air Force Office of Scientific Research, the MIT/MTL Samsung Semiconductor Research Fund, the Sagol WIS-MIT Bridge Program, the National Science Foundation, the Gordon and Betty Moore Foundation, and the Ramon Areces Foundation.
Never miss a breakthrough: Join the SciTechDaily newsletter.
Follow us on Google and Google News.