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

The recent studies of magno-assisted tunnelling in ferromagnetic van der Waals heterostructures formed by graphene and ultrathin CrBr 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/CrBr (Gr/CrBr) 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/CrBr and CrBr/Gr/CrBr 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/CrBr 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.