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. [ABSTRACT FROM AUTHOR]