Emergent quantum valley Hall insulator from electron interactions in transition-metal dichalcogenide heterobilayers
Phys. Rev. B 113, 165413 – Published 15 April, 2026
DOI: https://doi.org/10.1103/v5h1-2syy
Abstract
We explore the emergence of topological phases in moiré bilayer, highlighting the crucial role of spin-orbit coupling and Coulomb interactions at two holes per moiré unit cell . Our analysis uncovers robust quantum valley Hall insulating phase and reveals that long-range interactions alone can mediate the interlayer electron tunneling, generating topologically nontrivial bands even in the absence of the corresponding single-particle hopping. Additionally, we show that in the case of band mixing terms originating both from the interaction and single-particle physics, a competition between topological states realizing -wave and symmetries can appear. Moreover, within the considered theoretical framework, we present that by introducing a small Zeeman field, one can lift the band inversion in one of the valleys. This leads to a quantum anomalous Hall insulating state with the topological gap opening in a single valley and the other being topologically trivial.