Programmable optical tweezer for magnetic skyrmions

Magnetic skyrmions are localized magnetization swirls with unitary topological charges Their topological protection against external perturbations and high electrical mobility under low current density make skyrmions strong candidates for energy-efficient information carriers in memory devices, logics, and unconventional computing architectures. However, precise and individual control of skyrmions using electrical manipulations remains challenging. Skyrmions deflects due to the skyrmion Hall effect at high current densities and stochastic motion at low current densities. Precise and programmable control of individual skyrmions is crucial for both systematic investigations of their fundamental behavior and the reliable operation of skyrmionic devices.

Since their invention in 1970, optical tweezers have revolutionized diverse research fields from quantum physics to biological sciences. The ability to precisely manipulate particles, ranging from microspheres to single atoms, has enabled studies of inter-particle interactions, on-demand preparation of ensembles for quantum simulations, and the exploration of single-particle dynamics at the microscopic view. Extending optical tweezers, which have conventionally been limited to manipulating real particles, into the realm of quasiparticles is timely and relevant for exploring emergent phenomena and advanced applications encoded in their dynamics.

In this research, I demonstrate an optical spin tweezer for programmable manipulation of individual magnetic skyrmions. A tightly focused laser beam generates a local potential well via photothermal heating, which traps magnetic skyrmions and allows their positioning with submicron precision., even against spin–orbit torque (SOT)-driven motion. Beyond conventional optical tweezers, photothermal manipulation offers expanded functionality, including deterministic creation and annihilation of single skyrmions.(1)    A full set of trapping, transport, creation, and annihilation completes programmable manipulation of individual skyrmions. By integrating our innovative optical manipulation technique with conventional electrical current-driven transport, we demonstrate fully programmable control of skyrmions in two dimensions.