Gigahertz manipulation of magnetic skyrmions by microwave fields

We theoretically investigate the inertial dynamics of magnetic skyrmions driven by the microwave-induced inverse Faraday effect (MIFE) of circularly polarized microwaves (CPM). By incorporating an inertial mass and MIFE force, we demonstrate fundamentally distinct dynamical regimes under continuous-wave (CW) versus pulsed excitation. Skyrmion inertia transforms trajectories from smooth spirals to polygonal orbits under CW driving and enables sustained post-pulse gyration. Handedness is determined by the topological charge and CPM helicity: left-circularly polarized (LCP) CPM attracts skyrmions toward the beam center, whereas right-circularly polarized (RCP) CPM repels them. Systematic parameter analysis reveals how Gilbert damping, CPM intensity, frequency, and skyrmion mass control the oscillatory-to-overdamped transition. Our work identifies inertia, topological charge, and CPM helicity as essential factors for GHz-frequency skyrmion manipulation.