Chiral superconductors and competing states across a Lifshitz transition in rhombohedral pentalayer graphene

Chuanqi Zheng; Cheng Xu; Chushan Li; Chenyu Zhang; Zijing Zhang; Kenji Watanabe; Takashi Taniguchi; Hao Yang; Dandan Guan; Liang Liu; Shiyong Wang; Yaoyi Li; Hao Zheng; Canhua Liu; Jinfeng Jia; Shengwei Jiang; Zhiwen Shi; Guorui Chen; Fengcheng Wu; Yang Zhang; Tingxin Li; Xiaoxue Liu

arXiv · 2608.29873

Chiral superconductors and competing states across a Lifshitz transition in rhombohedral pentalayer graphene

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Abstract

Rhombohedral multilayer graphene hosts a distinctive low-energy electronic structure in which strong Coulomb interactions and nontrivial quantum geometry intertwine to generate exotic quantum states. Recent experiments reported signatures of chiral superconductivity in electron-doped rhombohedral multilayer graphene within the spin- and valley-polarized regime. Here we map the normal-state fermiology surrounding chiral superconductivity in rhombohedral pentalayer graphene. Quantum oscillation measurements reveal an electrically controlled Lifshitz transition between a simply-connected circular quarter-metal Fermi surface and an annular quarter-metal Fermi surface. The Lifshitz boundary itself shifts with perpendicular magnetic field, consistent with the strongly momentum-dependent orbital magnetic moment of the low-energy band. Approaching the transition from either side, the electron effective mass becomes strongly enhanced, implying the formation of a nearly dispersionless band bottom and a strongly reduced kinetic-energy scale. This singular electronic structure produces a regime of exceptionally strong instability in which chiral superconductivity competes with Wigner crystalline phases and reentrant quantum Hall states. In particular, two superconducting regions with signatures of orbital time-reversal-symmetry breaking lie on opposite sides of the Lifshitz boundary and have comparable transition temperatures, yet the annular-side state is suppressed by a substantially smaller perpendicular magnetic field. Our calculation finds comparable chiral pairing tendencies on the two parent Fermi surfaces while producing a much lower orbital-Zeeman pair-breaking scale and an additional finite-momentum pairing tendency for the annular state. These results identify Fermi-surface topology as a key control parameter for chiral superconductivity in rhombohedral graphene.

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Chuanqi Zheng, Cheng Xu, Chushan Li, Chenyu Zhang, Zijing Zhang, Kenji Watanabe, Takashi Taniguchi, Hao Yang, Dandan Guan, Liang Liu, Shiyong Wang, Yaoyi Li, Hao Zheng, Canhua Liu, Jinfeng Jia, Shengwei Jiang, Zhiwen Shi, Guorui Chen, Fengcheng Wu, Yang Zhang, Tingxin Li, Xiaoxue Liu. 2026-08-30. Chiral superconductors and competing states across a Lifshitz transition in rhombohedral pentalayer graphene. https://arxiv.org/abs/2608.29873

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