Speaker
Description
The quantum anomalous Hall effect (QAH) effect, characterized by quantized Hall resistance and vanishing longitudinal resistance at zero magnetic field, is a novel quantum phase of matter induced by the interplay between nontrivial band topology and spontaneous magnetic order. It has been realized in a wide variety of materials and heterostructures, and may have unique applications in topological electronics and spintronics.
In this talk, we present the manipulation of the QAH effects in three different types of topological materials. In the conventional ferromagnetic QAH effect realized in magnetically doped topological insulator thin films, an inplane magnetic field suppresses the quantization and reduces the coercive field, which can be explained by coherent domain rotation. In the antiferromagnetic QAH effect in odd-number-layer MnBi2Te4 flakes covered with AlOx, the quantization is enhanced and the coercive field becomes larger in inplane magnetic fields, reflecting the unique spin flop transition in a layered antiferromagnet. In the orbital-ferromagnetic QAH effect achieved in multilayer rhombohedral graphene morie system, inplane magnetic fields cause a reversal of the Chern number due to the coupling of spin and orbital degrees of freedom. The versatile tunability of the three types of QAH effects demonstrate the rich phenomenology in topological quantum materials and may pave the way for potential device applications.