Dynamics of the collapse of a ferromagnetic skyrmion in a centrosymmetric lattice

TL;DR

This study analyzes how ferromagnetic skyrmions in a lattice evolve and collapse over time, revealing the effects of lattice interactions, magnetic fields, and damping on skyrmion stability and dynamics.

Contribution

It provides a combined analytical and numerical investigation of skyrmion collapse mechanisms in a centrosymmetric lattice, highlighting the role of lattice and magnetic field effects.

Findings

Lattice and magnetic field induce strong time dependence of skyrmion chirality.

Intrinsic damping from nonlinearity causes skyrmion collapse via spin wave emission.

Collapse speed increases exponentially with magnetic field presence and damping.

Abstract

Time dependence of the size and chirality of a ferromagnetic skyrmion in a Heisenberg model with the magnetic field on a square lattice has been studied analytically and numerically. The lattice and the magnetic field generate strong time dependence of the skyrmion chirality. Due to nonlinearity, the lattice alone also generates strong intrinsic damping that leads to the skyrmion collapse via the emission of spin waves. In the absence of the magnetic field the collapse is slow for a large skyrmion but it becomes exponentially fast in the presence of the Landau-Lifshitz damping when the field is turned on. Magnons emitted by a collapsing skyrmion must have a discrete spectrum due to the quantization of the skyrmion magnetic moment.