Photoinduced Picosecond-Scale Radial Current for Generating and Converting Spin Textures.

Magnetic skyrmions are topologically protected spin textures characterized by their whirling structure, high stability, and potential for next-generation magnetic devices. However, their practical implementation has been hindered by the absence of methods for ultrafast and energy-efficient skyrmion writing and erasure. We theoretically propose the generation of a picosecond-scale photoinduced radial current that produces an azimuthally polarized spin-orbit torque in a heavy-metal/ferromagnet heterostructure. This approach enables ultrafast (< 50 ps) generation and controlled transitions between four distinct types of topological skyrmionic quasiparticles. Our results establish a versatile platform for optically controlled topological magnetism and open pathways for high-speed, low-power spin-based memory and logic technologies.