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 C3 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 C3-symmetry breaking strongly reshapes the Bloch wave functions 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 et al., 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.

Source-reported materials — not catalogue approval

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