Direct observation of antiferromagnetic parity violation in the electronic structure of Mn2Au

Abstract

Using momentum microscopy with sub-μm spatial resolution, allowing momentum resolved photoemission on individual antiferromagnetic domains, we observe an asymmetry in the electronic band structure, E(k)≠E(-k), in Mn2Au. This broken band structure parity originates from the combined time and parity symmetry, PT, of the antiferromagnetic order of the Mn moments, in connection with spin-orbit coupling. The spin-orbit interaction couples the broken parity to the Néel order parameter direction. We demonstrate a novel tool to image the Néel vector direction, N, by combining spatially resolved momentum microscopy with ab-initio calculations that correlate the broken parity with the vector N.