Quantized Topological States in High-quality Intrinsic Magnetic Topological Insulator MnBi₂Te₄

As an intrinsic magnetic topological insulator, MnBi₂Te₄ features both magnetism and non-trivial band topology without the need for the magnetic dopants that limit the quality of the material. As a result, zero-field quantum anomalous Hall (QAH) effect has been observed in a five-septuple-layer (5SL) MnBi₂Te₄. In this talk, I will show that improved sample quality leads to better quantization of the QAHE at higher temperatures. Furthermore, more quantized topological states emerge in high magnetic field up to 45 T, as a result of intricate interplay between QAH and conventional quantum Hall effects. Our findings pave the way for exploring topological quantum phenomena such as chiral Majorana edge state and topological superconductivity.