Quantized planar Hall transport in magnetic topological insulators

When long-range ferromagnetic order is introduced into 2D topological insulator (TI) films, the exchange energy opens a gap in the surface Dirac states, giving rise to quantum anomalous Hall (QAH) states. In this presentation, we discuss recent advancements in understanding the quantized transport behavior in molecular beam epitaxy (MBE) grown 2D magnetic topological insulator (MTI). We report, for the first time, a robust quantized planar Hall conductivity under in-plane magnetic fields under a large in-plane magnetic field in a magnetic topological insulator. Furthermore, the topological phase transitions between QAH insulator, half-quantized Hall conductance states (hQHC), and axion insulator states are observed under different magnetization configurations in the single material platform. Angle-resolved magneto-transport measurements provide detailed information on different perpendicular magnetic anisotropy energies of top and bottom surface magnetism and provide insights into the manipulation of the topological magnetoelectric effect via field orientation.