Room-Temperature Superconductors: MIT's Quantum Leap Forward

MIT physicists have observed clear evidence of unconventional superconductivity in magic-angle twisted tri-layer graphene, or MATTG. Superconductors allow electric current to flow without resistance, but conventional superconductors require extremely low temperatures.

The findings, published in the journal Science, indicate that MATTG's superconducting gap differs significantly from that of traditional superconductors, suggesting a new mechanism for superconductivity.

The superconducting gap reflects the strength of the superconducting state at various temperatures. Co-lead author Shuwen Sun pointed out that understanding these gaps could lead to the development of room-temperature superconductors, which has the potential to revolutionize energy grids and quantum computing.

Researchers utilized a novel experimental system to directly observe how the superconducting gap forms in two-dimensional materials. They plan to apply this method to MATTG and other similar materials to identify candidates for advanced technologies.

The concept of 'twistronics' emerged from earlier research indicating that stacking graphene layers at precise angles could yield new electronic behaviors. In 2018, the first experimental production of magic-angle graphene opened new pathways in this field.

Superconductivity arises when electrons form pairs known as Cooper pairs, which can move through a material without resistance. In contrast to conventional superconductors where electrons are loosely bound, MATTG exhibits tightly bound electron pairs, hinting at its unique superconducting properties.

To confirm MATTG's superconductivity, the MIT team employed tunneling spectroscopy, a quantum-scale technique that measures how easily electrons can tunnel through a material. Their new platform combines tunneling spectroscopy with electrical transport measurements, allowing for a clearer view of the superconducting gap.

Notably, the superconducting gap in MATTG displayed a distinct V-shaped curve when the material reached zero resistance, indicative of a different superconducting mechanism. Co-lead author Jeong Min Park stated that this demonstrates MATTG's unconventional behavior.

Unlike conventional superconductors where electron pairing is influenced by atomic lattice vibrations, in MATTG, strong electronic interactions likely drive this pairing. The MIT team intends to explore other twisted and layered materials using their cutting-edge techniques, which could shed light on the underlying electronic structures of superconductivity.

This research could pave the way for designing new superconductors and quantum materials, with implications for more efficient technologies and advanced quantum computing. The project received support from multiple organizations, including the U.S.

Army Research Office and the National Science Foundation.