Coexistence of Superconductivity and Chern insulators with |C| $\geq 1$ in twisted rhombohedral bilayer-trilayer graphene

Rhombohedral multilayer graphene (RMG) has been demonstrated as a promising platform for investigating strongly correlated phases of matter. Here, we observe a coexistence of superconductivity and Chern insulators in a twisted rhombohedral bilayer-trilayer graphene moiré superlattice. Superconductivity, evidenced by a sharp transition with a critical temperature of ~180 mK, nonlinear I-V with a BKT temperature of 135 mK, and a signature of phase-sensitive interference patterns, emerges from a symmetry-breaking Fermi surface near v = -2 and D = 0, and it survives at a large in-plane magnetic field up to 2 T, strongly deviating from the Pauli limit. Moreover, we observe a strong modulation of the Ginzburg-Landau coherence length from 467 nm to 145 nm as the in-plane magnetic field increases from 0 to 2 T, whereas the critical current Ic barely changes. Unlike previous studies in RMG, we observe a competition between superconductivity and a correlated insulator at v = -2, monitored by displacement fields and twist angles. Note that we also observe integer Chern insulators with C = 1, 3, and -3 at v = 1/2, 1, and 3, respectively, for large D > 0 in the same superconducting device. The observations establish twisted rhombohedral graphene multilayers as a fascinating system to investigate unconventional superconductivity, high Chern number topology, and their interplay.

Authors

Publication Details

Journal
arXiv (Cornell University)
Published
2026-10-29
DOI
https://doi.org/10.48550/arxiv.2610.40170
Primary Topic
Graphene research and applications
Type
preprint
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preprint

Coexistence of Superconductivity and Chern insulators with |C| $\geq 1$ in twisted rhombohedral bilayer-trilayer graphene

Guangyu Zhang, Weibo Gao, Takashi Taniguchi, Fankun Wang et al.
arXiv (Cornell University)
Graphene research and applications
preprint

Coexistence of Superconductivity and Chern insulators with |C| $\geq 1$ in twisted rhombohedral bilayer-trilayer graphene

Guangyu Zhang, Weibo Gao, Takashi Taniguchi, Fankun Wang, Zihao Huo, Xiaobo Lu, Le Liu, Tianqi Song, Jingwei Dong, Qiu Yang, Wei Yang, Kenji Watanabe
preprint en

Abstract

Rhombohedral multilayer graphene (RMG) has been demonstrated as a promising platform for investigating strongly correlated phases of matter. Here, we observe a coexistence of superconductivity and Chern insulators in a twisted rhombohedral bilayer-trilayer graphene moiré superlattice. Superconductivity, evidenced by a sharp transition with a critical temperature of ~180 mK, nonlinear I-V with a BKT temperature of 135 mK, and a signature of phase-sensitive interference patterns, emerges from a symmetry-breaking Fermi surface near v = -2 and D = 0, and it survives at a large in-plane magnetic field up to 2 T, strongly deviating from the Pauli limit. Moreover, we observe a strong modulation of the Ginzburg-Landau coherence length from 467 nm to 145 nm as the in-plane magnetic field increases from 0 to 2 T, whereas the critical current Ic barely changes. Unlike previous studies in RMG, we observe a competition between superconductivity and a correlated insulator at v = -2, monitored by displacement fields and twist angles. Note that we also observe integer Chern insulators with C = 1, 3, and -3 at v = 1/2, 1, and 3, respectively, for large D > 0 in the same superconducting device. The observations establish twisted rhombohedral graphene multilayers as a fascinating system to investigate unconventional superconductivity, high Chern number topology, and their interplay.

arXiv (Cornell University)
Graphene research and applications
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