  In this study, we investigate intrinsic magnetic topological insulator
MnBi2Te4 thin films grown by molecular beam epitaxy. We observe a reentrant
quantum anomalous Hall effect when the Fermi energy enters the valance band and
magnetic field equals zero, indicating the emergence of the Chern Anderson
insulator state. The discovery opens a new avenue for realizing the QAH effect
and underscores the fundamental role of both Berry curvature and Anderson
localization.
