Direct Observation of Antiferromagnetic Parity Violation in the Electronic Structure of Mn2Au

Abstract Parity symmetric photoemission spectra are ubiquitous in solid state research, being prevalent in many highly active areas, such as unconventional superconductors, nonmagnetic and antifer- romagnetic topological insulators, and weakly relativistic collinear magnets, among others. The direct observation of parity-violating metallic Kramers degenerate bands has remained hitherto experimentally elusive. Here we observe the antiferromagnetic parity violation (APV) in the bandstructure of Mn2Au thin films by using momentum microscopy with sub-µm spatial resolution, allowing momentum resolved photoemis- sion on single antiferromagnetic domains. The APV arises from breaking the P symmetry of the underlying crystal structure by the collinear antiferromagnetism, while preserving the joint space-time inverison PT -symmetry and in combination with large spin-orbit coupling. In addition, our work also demonstrates a novel tool to directly image the Néel vector direction by com- bining spatially resolved momentum microscopy with ab-initio calculations.