First-principles calculations of magneto-optical Kerr effect in high Neel temperature antiferromagnetic Metals

Recent developments in spintronics have suggested the use of high Neel temperature antiferromagnetic (AFM) materials in memory devices due to their vanishing stray fields and robust magnetic structure for ultra-fast spin dynamics in the terahertz regime. In particular, the optical response of these magnetic materials via the Kerr effect (MOKE) provides an excellent method to probe surface magnetization and elucidate the AFM state under external magnetic fields. In this work, we use first-principles density functional theory calculations to obtain the fully relativistic dielectric tensor to predict MOKE signals for Cr₂As, Mn₂As, Fe₂As, MnPt and Mn₂Au under external magnetic fields. We further corroborate experimental measurements by obtaining the magnetic susceptibility from first principles using a spin-tilting method. Finally, we explore the implications of applying external magnetic bias in AFMs by interpreting the electronic band structure and its evolution with respect to spin-orbit coupling and magnetization, to better understand the origins of the predicted MOKE signals.