Dynamics of Skyrmion Crystals in Metallic Thin Films

TL;DR

This paper investigates the collective dynamics of Skyrmion crystals in metallic thin films, revealing how current-driven motion affects topological Hall effects, introduces a new dissipation mechanism, and explores phonon dispersion and impurity effects.

Contribution

It presents new insights into Skyrmion crystal dynamics, including a novel dissipation mechanism and detailed analysis of phonon dispersion and impurity pinning effects.

Findings

Current-driven motion reduces topological Hall effect.

Skyrmion trajectories bend away from current direction.

Identifies a new dissipation mechanism leading to faster spin relaxation.

Abstract

We study the collective dynamics of the Skyrmion crystal (SkX) in thin films of ferromagnetic metals resulting from the nontrivial Skyrmion topology. We show that the current-driven motion of the crystal reduces the topological Hall effect and the Skyrmion trajectories bend away from the direction of the electric current (the Skyrmion Hall effect). We find a new dissipation mechanism in non-collinear spin textures that can lead to a much faster spin relaxation than Gilbert damping, calculate the dispersion of phonons in the SkX, and discuss effects of impurity pinning of Skyrmions.