MIT Researchers Confirm Unconventional Superconductivity in Twisted Graphene

Researchers affiliated with the Massachusetts Institute of Technology (MIT) have documented definitive evidence of unconventional superconductivity within magic-angle twisted trilayer graphene (MATTG), a material engineered by precisely stacking and twisting layers of carbon atoms.

The experimental breakthrough centered on the direct detection of a characteristic V-shaped superconducting gap, which serves as the most unambiguous confirmation to date that this material operates outside the paradigm of conventional superconductivity. The team deployed a novel platform integrating both electron tunneling and electrical transport measurements to directly map this gap in the MATTG structure. The distinct V-shaped profile manifested precisely when the material achieved a state of zero electrical resistance, a hallmark of superconductivity, according to findings published in the journal Science.

The research team, which included co-lead authors Shuwen Sun, an MIT graduate student, and Jeong Min Park, posits that the V-shaped gap points toward a more robust pairing mechanism driven by strong electronic interactions, rather than the phonon-mediated interactions typical of conventional superconductors. This distinction is critical because conventional pairing is notoriously susceptible to thermal disruption, whereas an interaction-driven mechanism could theoretically pave the way for more stable, potentially higher-temperature superconducting applications.

Superconductivity, the phenomenon where electrons pair up to flow without energy loss, is a long-standing pursuit for technological advancement in areas like lossless energy transmission and high-speed computing. Conventional superconductors rely on lattice vibrations, or phonons, to facilitate electron pairing, a mechanism that limits their operational temperature and stability. The MATTG system, where electron-electron repulsion and correlation effects dominate, provides a platform where this research validates theoretical models suggesting strong correlation effects can stabilize superconductivity in atomically thin structures.

The methodological achievement in this study is significant, as the development of an experimental setup capable of unambiguously resolving the superconducting tunneling gap in MATTG represents a major advance in measurement science. Unconventional superconductors, including those in twisted graphene systems, defy the established Bardeen-Cooper-Schrieffer (BCS) theory. By isolating the V-shaped gap signature, the MIT-led team has provided a crucial experimental fingerprint to refine theoretical frameworks attempting to explain non-phonon-mediated pairing.

The research effort acknowledged contributions from Kenji Watanabe and Takashi Taniguchi of the National Institute for Materials Science in Japan, underscoring the international nature of advanced materials science collaboration. This observation reinforces the potential of van der Waals heterostructures to host novel electronic states, moving the field closer to designing materials where superconductivity is robust enough to transition from fundamental physics curiosity to transformative technology.