Efficient motion of 90° domain walls in Mn2Au via pure optical torques

Discovering alternative ways to drive domain wall (DW) dynamics is crucial for advancing spintronic applications. Here we demonstrate via atomistic spin dynamics simulations that a novel laser optical torque (LOT) excited in the visible spectrum can efficiently drive 90° DWs in the Mn2Au antiferromagnet but its spatial symmetry forbids the motion of 180° walls. In the steady-state regime, the kinematics display special relativity signatures accessed for low laser intensities. At velocities higher than the magnonic limit, the DW enters a proliferation regime in which part of its relativistic energy is invested into the nucleation of novel magnetic textures. The unique LOT symmetry allows the precise control of the DW motion direction rotating the laser polarisation or tailoring the wall chirality. Our investigation contributes towards the fundamental understanding of opto-magnetic effects, supporting the development of next-generation, all-optically controlled antiferromagnetic spintronics.