Skyrmion Mass from Spin-Phonon Interaction

TL;DR

This paper calculates the inertial mass of skyrmions caused by spin-phonon interactions in ferromagnetic films, revealing how it depends on material and geometric parameters, which impacts skyrmion-based information processing.

Contribution

It provides an exact computation of skyrmion mass from spin-phonon coupling within a simplified model, highlighting its dependence on coupling strength, film thickness, and skyrmion size.

Findings

Skyrmion mass scales quadratically with magnetoelastic coupling strength.

Mass increases linearly with skyrmion size.

Estimated mass for nanometer skyrmions is a few electron masses.

Abstract

Inertial mass of a skyrmion arising from spin-phonon interaction is computed exactly within a toy model of the magnetoelastic coupling in a ferromagnetic film. The mass scales as the square of the strength of the magnetoelastic coupling, as the square of the film thickness, and as the first power of the lateral size of the skyrmion. For nanometer skyrmions it is in the ballpark of a few electron masses but may be significantly greater in materials with large magnetostriction. These findings are expected to stand for any complex structure of spin-phonon interaction in real materials. They must be taken into account when addressing the speed of information processing based upon skyrmions.