Light-induced Dzyaloshinskii-Moriya interactions in antiferromagnetic metals

The Dzyaloshinskii-Moriya (DM) interaction plays an essential role in novel topological spintronics, and the ability to control this chiral interaction is of key importance. Developing a general microscopic framework to compute nonequilibrium DM interactions, we theoretically show that the ac electric field component of a laser pulse induces nonequilibrium static DM interactions in an antiferromagnetic (AFM) system in the presence of relativistic spin-orbit coupling. These nonequilibrium DM interactions might even be anisotropic depending on the direction of magnetic moments and the laser pulse polarization. We further show that intense polarized laser pulses can in principle generate both classes of DM interactions, i.e., bulk-type and interfacial-type, in a magnetic system even though the crystal symmetry prohibits one of them in equilibrium. Our results reveal another aspect of rich behavior of periodically driven spin systems and the far-from-equilibrium magnetic systems.