Skyrmion dynamics in a chiral magnet driven by periodically varying spin currents

TL;DR

This paper explores how alternating spin currents influence skyrmion motion in chiral magnets, revealing periodic trajectories driven by forces from damping and torque effects, using numerical and analytical methods.

Contribution

It demonstrates the dynamic behavior of skyrmions under ac currents and explains the motion through combined numerical simulations and the Thiele equation analysis.

Findings

Skyrmions follow periodic trajectories under ac spin currents.

The motion results from Magnus and viscous forces due to damping and torque effects.

Numerical solutions align with analytical Thiele equation predictions.

Abstract

In this work, we investigated the spin dynamics in a slab of chiral magnets induced by an alternating (ac) spin current. Periodic trajectories of the skyrmion in real space are discovered under the ac current as a result of the Magnus and viscous forces, which originate from the Gilbert damping, the spin transfer torque, and the $ \beta $-nonadiabatic torque effects. The results are obtained by numerically solving the Landau-Lifshitz-Gilbert equation and can be explained by the Thiele equation characterizing the skyrmion core motion.