Possible realization of the high-temperature and multichannel quantum anomalous Hall effect in graphene/CrBr3 heterostructures under pressure

Abstract

The recent studies of magno-assisted tunnelling in ferromagnetic van der Waals heterostructures formed by graphene and ultrathin CrBr₃ films (D. Ghazaryan et al., Nat. Electron., 2018, 1, 344) offer broader opportunities for exploration of novel quantum phenomena, especially for realizing the graphene-based quantum anomalous Hall effect (QAHE). Based on first-principles approaches, we reveal that three types of graphene/CrBr₃ (Gr/CrBr₃) heterostructures exhibit metallic band behavior due to strong charge-transfer at the interfaces of these heterosystems. Remarkably, the pressure-induced QAHE can be achieved in Gr/CrBr₃ and CrBr₃/Gr/CrBr₃ systems. Further low energy k·p model analyses show that the nontrivial topological properties are mainly attributed to the Rashba spin–orbit coupling (SOC), but not to the intrinsic SOC of graphene. Moreover, a multichannel device prototype is proposed in the superlattices composed of Gr/CrBr₃ and normal insulator (such as hexagonal boron nitride) layers. Our work provides an experimentally feasible scheme for realizing the high-temperature and multichannel QAHE in graphene-based heterostructures.