Quantum Anomalous Hall Effect in Magnetic Insulator Heterostructure

TL;DR

This paper predicts a new quantum anomalous Hall insulator in magnetic insulator heterostructures using ab initio calculations, highlighting a novel mechanism of band inversion without magnetic doping.

Contribution

It introduces a new approach to realize quantum anomalous Hall states through band inversion in heterostructures of topologically trivial insulators.

Findings

Predicted a monolayer heterostructure as a quantum anomalous Hall insulator with a 38 meV band gap.

Proposed a simple model explaining spin polarized band inversion mechanism.

Suggested realization of 3D quantum anomalous Hall insulator in superlattice structures.

Abstract

Based on ab initio calculations, we predict that a monolayer of Cr-doped (Bi,Sb)2Te3 and GdI2 heterostructure is a quantum anomalous Hall insulator with a non-trivial band gap up to 38 meV. The principle behind our prediction is that the band inversion between two topologically trivial ferromagnetic insulators can result in a non-zero Chern number, which offers a better way to realize the quantum anomalous Hall state without random magnetic doping. In addition, a simple effective model is presented to describe the basic mechanism of spin polarized band inversion in this system. Moreover, we predict that 3D quantum anomalous Hall insulator could be realized in (Bi2/3Cr1/3)2Te3/GdI2 superlattice.