Anomalous Hall Effect Due to Magnetic Canting Phase in MnBi₂Te₄

The intrinsic magnetic topological insulator, MnBi₂Te₄, is an exciting material predicted to host a variety of quantum states, such as the quantum anomalous Hall insulator, the Weyl semimetal, and the axion insulator. Despite the rapid progress, the study of this material has generated many unanswered questions that have inspired experimental developments. Here, we experimentally observed an intrinsic anomalous Hall effect (AHE) in MnBi₂Te₄ sensitive to the perpendicular magnetic moments and to its canting angle. MnBi₂Te₄ was grown by molecular beam epitaxy on GaAs(111)B, which is allowed us to obtain a large area of 24-layer MnBi₂Te₄. AHE measurements yield the phase diagram that includes an antiferromagnetic response followed by the surface spin-flop transition, a canted phase, and a ferromagnetic state. Throughout this evolution, the AHE is scaling super-linear with magnetization rather than linearly. We demonstrate that this super-linear scaling is related to the canted angle and consistent with the symmetry of the crystal. Our findings suggest that novel topological responses may be found in non-collinear ferromagnetic and antiferromagnetic phases.