An ab-initio study on engineering quantum anomalous Hall effect in compensated antiferromagnet MnBi$_{2}$Te$_{4}$

TL;DR

This study demonstrates the realization of the quantum anomalous Hall effect in compensated antiferromagnetic MnBi₂Te₄ using first-principles calculations, pressure tuning, and heterostructure design, expanding potential for room-temperature topological devices.

Contribution

It provides the first systematic ab-initio demonstration of QAHE in MnBi₂Te₄ without relying on $ ext{PT}$ symmetry, and explores pressure and heterostructure methods to enhance and realize QAHE.

Findings

QAHE can be realized in MnBi₂Te₄ without $ ext{PT}$ symmetry.

External pressure can increase the topological gap beyond room temperature.

Heterostructures with CrI₃ can induce QAHE in MnBi₂Te₄.

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 ($\mathcal{PT}$) 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.