Evolution of Berry curvature and reentrant quantum anomalous Hall effect in an intrinsic magnetic topological insulator

Recently, the magnetic topological insulator (TI) MnBi2Te4 emerged as a competitive platform to realize quantum anomalous Hall (QAH) states. We report a Berry curvature splitting mechanism to realize the QAH effect in the disordered magnetic TI multilayers when switching from an antiferromagnetic order to a ferromagnetic order. We reveal that the splitting of spin-resolved Berry curvature, originating from the separation of the critical points during the magnetic switching, can give rise to a QAH insulator. We present a global phase diagram, and also provide a phenomenological picture to elucidate the Berry curvature splitting mechanism by the evolution of topological charges. At last, we predict that the Berry curvature splitting mechanism will lead to a reentrant QAH effect, which can be detected by tuning the gate voltage. Our theory will be instructive for the studies of the QAH effect in MnBi2Te4 in future experiments.

Automated summary

By studying the Berry curvature splitting mechanism in multilayers of magnetic topological insulators, the quantum anomalous Hall effect can be realized. The splitting of Berry curvature during magnetic switching leads to the generation of a QAH insulator, which can be detected by tuning the gate voltage.