Imaging the surface electronic states in the family of magnetic “topological” EuM2X2

Gapping of Dirac surface states through time reversal symmetry breaking may realize the axion insulator state in condensed matter. Despite tremendous efforts, only few material systems fall into this category of intrinsic magnetic topological insulators. Recent theoretical calculations proposed the antiferromagnetic EuM2X2 family of materials to be topologically nontrivial magnetic insulator/semimetals. In this talk, I will present our recent experimental findings of the surface electronic states in the family of EuM2X2 (M = In, Zn, Cd; X = As, Sb) using scanning tunneling microscopy and spectroscopy, complemented with density-functional theory calculations.