An ab-initio study on engineering quantum anomalous Hall effect in compensated antiferromagnet MnBi${}_2$Te${}_4$

Abstract

Recently, the quantum anomalous Hall effect (QAHE) has been theoretically proposed in compensated antiferromagnetic systems by using the magnetic topological insulator model [see arXiv:2404.13305 (2024)]. However, the related and systematic study based on a realistic material system is still limited. As the only experimentally realized antiferromagnetic topological insulator, MnBi${}_2$Te${}_4$ becomes a vital platform for exploring various topological states. In this work, by using the comprehensive first-principles calculations, we demonstrate that the QAHE can also be realized in compensated antiferromagnetic even-septuple-layer MnBi${}_2$Te${}_4$ without combined parity-time ($\mathcal{P}\mathcal{T}$) symmetry. Using a magnetic topological insulator model, the layer-resolved Chern number is calculated to further understand the physical origin of different Chern numbers. The application of external hydrostatic pressure can strengthen the Te-Te quasicovalent bond due to the dramatic compression of the van der Waals gap. Thus, the resulting topological nontrivial gap can exceed the room-temperature energy scale in a wide range of pressures. Additionally, we find that constructing MnBi${}_2$Te${}_4$/CrI${}_3$ heterostructure can realize the compensated antiferromagnetic configurations with QAHE. Our findings illustrate the realization of QAHE in compensated antiferromagnetic even-septuple-layer MnBi${}_2$Te${}_4$ and provide a reliable strategy to obtain the corresponding magnetic configurations.