MnBi2Te4 – a good platform for topological quantum physics study
Weilun Tan, Jing Liu, Hui Li, Dandan Guan, Jinfeng Jia
Abstract
Abstract Magnetic topological insulator MnBi 2 Te 4 is an intrinsic van der Waals layer structure compound. The interplay between magnetism and topology makes MnBi 2 Te 4 a good platform to investigate controllable topological phase transition and emerging physical states such as quantum anomalous Hall state and Weyl semimetal phase. Crystal characterization showed a rhombohedral unit cell composing of Te-Bi-Te-Mn-Te-Bi-Te septuple layer (SL) coupled antiferromagnetically. Systematically investigation of surface states with angle-resolved photoemission spectroscopy and of bulk states with transport measurement showed detailed electronic structure of MnBi 2 Te 4 crystal. Rich topological phases were observed in MnBi 2 Te 4 . Temperature, doping and external magnetic field could affect the different topological phases and induce phase transitions in certain conditions. Quantum anomalous Hall effect (QAHE) was realized at as high as 6.5 K in 5-SLs MnBi 2 Te 4 flake. Furthermore, the negative to positive magnetoresistance transition and the thickness dependent QAHE Chern number of MnBi 2 Te 4 provide strong evidences for the Weyl semimetal states in this material. Based on experiments done from 2019 to 2022, our review should shed light on future research opportunities on MnBi 2 Te 4 compound.