Terahertz spin dynamics in antiferromagnetic Mn 2 Au

摘要: In antiferromagnets, the intrinsic terahertz (THz) magnon resonances are expected to enable pathways to high-speed spin information processing. In antiferromagnetic CuMnAs and Mn 2 Au, switching of the Néel vector has been demonstrated by using pulsed electrical currents and free-space THz pulses. The switching was attributed to the Néel spin-orbit torque (NSOT), which is proportional to the current. However, the underlying spin dynamics have not yet been studied on their natural, ie sub-picosecond, time scales. Here, we employ a THz-pump optical-probe setup to investigate spin dynamics in Mn 2 Au thin films in the small-perturbation regime. The direction of the average Néel vector was prealigned via a spin-flop transition in a magnetic field of 60 T. We observe a signal that scales linearly with the driving THz field and whose shape, frequency and symmetry is consistent with NSOT-driven spin dynamics …