Ultrafast Laser Driven Ferromagnetic-Antiferromagnetic Skyrmion Switching in 2D Topological Magnet.

Light-spin coupling is an attractive phenomenon from the standpoints of fundamental physics and device applications, and has spurred rapid development recently. Whereas the current efforts are devoted to trivial magnetism, the interplay between light and nontrivial spin properties of topological magnetism is little known. Here, using first principles, rt-TDDFT and atomic spin simulations, the evolution of topological spin properties of monolayer CrInSe under laser is explored, establishing the ultrafast ferromagnetic-antiferromagnetic skyrmion reversal. The physics correlates to the laser-induced significant spin-selective charge transfer, demagnetization, and time-dependent magnetic interactions. Especially, an essential switching from ferromagnetic to antiferromagnetic exchange is generated under light irradiation. More importantly, dynamics of topological magnetic physics shows that this process accompanies with the evolution of topological magnetism from ferromagnetic to antiferromagnetic skyrmions, manifesting intriguing interplay between light and topological spin properties. The work provides a novel approach toward the highly desired ultrafast control of topological magnetism.