Skyrmions Driven by Intrinsic Magnons

TL;DR

This paper investigates how oscillating magnetic fields influence skyrmion motion in magnetic insulators, revealing a resonance-driven unidirectional propagation due to magnon interactions.

Contribution

It introduces a quantum field theory model showing how ac magnetic fields induce skyrmion motion via intrinsic magnons, including dissipation effects and resonance phenomena.

Findings

Resonant ac fields cause unidirectional skyrmion movement.

Magnetic ac fields induce a transition from super-Ohmic to Ohmic dissipation.

Magnon coupling leads to novel skyrmion dynamics in nanowires.

Abstract

We study the dynamics of a skyrmion in a magnetic insulating nanowire in the presence of time-dependent oscillating magnetic field gradients. These ac fields act as a net driving force on the skyrmion via its own intrinsic magnetic excitations. In a microscopic quantum field theory approach we include the unavoidable coupling of the external field to the magnons, which gives rise to time-dependent dissipation for the skyrmion. We demonstrate that the magnetic ac field induces a super-Ohmic to Ohmic crossover behavior for the skyrmion dissipation kernels with time-dependent Ohmic terms. The ac driving of the magnon bath at resonance results in a unidirectional helical propagation of the skyrmion in addition to the otherwise periodic bounded motion.