In this talk, I will overview the developments in the field of magnetic topological insulators (MTIs) that led to the discovery of the intrinsic MTIs of the MnBi2Te4 family that attracts a great deal of attention nowadays. First, to describe the context in which materials such as MnBi2Se4 and MnBi2Te4 appeared in the research arena, I will discuss the magnetic doping and magnetic proximity effect approaches of introducing magnetism into a TI. Then, the two types of novel and promising interfaces involving MnBi2Te(Se)4 compounds will be discussed, as they are expected to show certain advantages over the latter two approaches. Next, the discovery of intrinsic MTIs of the MnBi2Te(Se)4 family will be overviewed. Finally, concerning current challenges of this field, we will consider in detail the issue of the Dirac point gap in the MnBi2Te4 topological surface state that has caused a lot of controversy recently.

Ref: M. M. Otrokov et al., Nature 576, 416–422 (2019).
M. Garnica, M. M. Otrokov et al., npj Quantum Materials 7, 7 (2022).


連絡教員　物理学系　平原　徹（内線2365）