Tuning the interplay of magnetism and band topology in magnetic topological materials

Magnetic topological material provides a great platform in discovering new topological states, such as the magnetic Weyl semimetal, axion insulators, Chern insulators, and the 3D quantum anomalous Hall (QAH) insulators. Since the interplay of magnetism and band topology determines their topological natures, understanding and manipulating the magnetism inside magnetic topological materials will be crucial[1,2]. In this talk, I will show that a continuous fine control of the magnetism in MnBi₄Te₇ topological insulator can be made by Sb doping. The first-principles calculations propose the band topology is modified and a type-I magnetic Weyl semimetal phase can be realized at intermediate dopings [3]. Furthermore, the magnetic state can be easily switched between antiferromagnetic and ferromagnetic by external pressure, resulting in one more knob to tune the magnetic topological state. Our study provides a rare tunable material platform to realize various topological states.