Spin-resolved band structure in the antiferromagnetic topological insulators MnBi₂Te₄ and MnBi₄Te₇

Intrinsic magnetic topological insulators MnBi₂Te₄(Bi₂Te₃)_n (n=0,1,2…) have been extensively studied over the last few years, as they are predicted to host many exotic topological quantum states. However, despite what theory has predicted, angle-resolved photoemission spectroscopy (ARPES) has yet to see a clear gap opening associated with the antiferromagnetic transition, and discrepancies remain between DFT and the complete electronic structure as measured in ARPES. Therefore, the fundamental properties of the material family still need to be further explored.



In this talk, we will present our spin-resolved ARPES spectra on MnBi₂Te₄ (n=0) and MnBi₄Te₇ (n=1), showing both in-plane and out-of-plane spin polarization of the surface states. We analyze the spin-orbital texture and compare it to the behavior of typical topological insulators such as Bi₂Te₃ as described by effective theory and ab initio calculations [1]. We discuss the implications of our analysis and how it aids in the understanding of the electronic structures.