- Letter
- Open Access
Topological order without band topology in moiré graphene
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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