Raman signatures on a van der Waals antiferromagnet

Mixing other exotic properties, such as magnetism or superconductivity, into a topological material has been drawing a lot of researchers’ attention due to its potential as quantum computation and realizing topological phenomena. MnBi₂Te₄ has been demonstrated to be the first intrinsic antiferromagnetic (AFM) topological insulator (TI) [1]. It consists of Bi₂Te₃ and Mn-Te bilayer. So far, most studies focused on magnetic properties or electronic structure of the bulk material via magnetic susceptibility, angle-resolved photo-emission spectroscopy, and magnetotransport [2]. When the material comes down to 2D limits, optical Raman spectroscopy becomes advantageous due to its sensitivity and strong layer-dependent characteristic in 2D materials. Raman peaks can also reflect spin interactions that are related to magnetic ordering [3], as well as in-plane magnetic anisotropy. In this project, we will correlate the optical Raman spectrum on MnBi₂Te₄ with its magnetic transition temperature (~25K) and the in-plane magnetic anisotropy.
[1] Y. Deng et al., arXiv:1904.11468 (2019)
[2] C. Hu et al., arXiv:1905.02154 (2019)
[3] J. -U. Lee et al., Nano Lett. 16, 7433 (2016)