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  • Letter
  • Open Access

Topological order without band topology in moiré graphene

Hui Liu1,*, Raul Perea-Causin1,†, Zhao Liu2,3,‡, and Emil J. Bergholtz1,§

  • 1Department of Physics, Stockholm University, AlbaNova University Center, 106 91 Stockholm, Sweden
  • 2Zhejiang Institute of Modern Physics, Zhejiang University, Hangzhou 310058, China
  • 3Zhejiang Key Laboratory of Micro-Nano Quantum Chips and Quantum Control, School of Physics, Zhejiang University, Hangzhou 310027, China

  • *Contact author: hui.liu@fysik.su.se
  • †Contact author: raul.perea.causin@fysik.su.se
  • ‡Contact author: zhaol@zju.edu.cn
  • §Contact author: emil.bergholtz@fysik.su.se

Phys. Rev. Research 8, L032039 – Published 3 September, 2026

DOI: https://doi.org/10.1103/jx5w-35z9

Abstract

The discovery of zero-field fractional Chern insulators (FCIs) in moiré materials has attracted intense interest in the interplay between topology and correlations. Here, we demonstrate that fractionalized topological order can emerge under realistic conditions even within a topologically trivial moiré band. Employing exact diagonalization of long-range Coulomb interactions projected into a trivial band of twisted multilayer graphene, we identify a set of incompressible Laughlin-like ground states exhibiting fractional quantized Hall conductance. We trace the origin of this FCI phase to the strongly inhomogeneous distribution of quantum geometry, which reshapes interaction effects independently of the band topology. Extending this heuristic quantum-geometric mechanism, we demonstrate that similarly unexpected Laughlin-like FCIs can also be stabilized in higher-Chern-number moiré bands under experimentally accessible conditions. Our results establish realistic scenarios under which many-body topological order can emerge independently of single-particle band topology.

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