Nematic Enhancement of Superconductivity in Multilayer Graphene via Quantum Geometry

Abstract

Multilayer graphene materials have recently emerged as a fascinating versatile platform for correlated electron phenomena, hosting superconductivity, fractional quantum Hall states, and correlated insulating phases. A particularly striking experimental observation is the recurring correlation between nematicity in the normal state -- manifested by spontaneous breaking of the underlying $C_3$ symmetry -- and the stabilization of robust superconducting phases. Despite its ubiquity across different materials, devices and experiments, this trend has thus far lacked a clear microscopic explanation. In this work, we identify a concrete mechanism linking nematic order to enhanced superconductivity. We demonstrate that $C_3$-symmetry breaking strongly reshapes the Bloch wavefunctions near the Fermi level, producing a pronounced enhancement and redistribution of the so-called quantum metric. This effect drastically amplifies superconducting pairing mediated by the quantum geometric Kohn-Luttinger mechanism [G. Shavit \it{et al.}, \href{https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.134.176001}{Phys. Rev. Lett. 134, 176001 (2025)}]. Our analysis reveals that nematicity naturally boosts the superconducting coupling constant in experimentally relevant density regimes, providing a compelling explanation for observed correlations. These results establish the central role of geometric effects in graphene superconductivity and highlight nematicity as a promising avenue for engineering stronger unconventional superconducting states.