Edge instability in a chiral stripe domain under an electric current and skyrmion generation

TL;DR

This paper explains how skyrmions are generated from chiral stripe domains under electric currents by simulating the dynamics of half skyrmions at the domain ends, aligning with recent experiments and predicting new generation methods.

Contribution

The study introduces a theoretical model based on half skyrmions at stripe ends to explain skyrmion creation under current, supported by experimental validation and new predictions.

Findings

Skyrmions are generated by bending or stretching stripe domains under current.

Half skyrmions at stripe ends drive the dynamics leading to skyrmion formation.

Skyrmions can also be generated in Bloch stripe domains in B20 compounds.

Abstract

Motivated by the recent experimental observations on the skyrmion creation by cutting chiral stripe domains under a current drive [Jiang {\emph{et al.}}, Science {\bf{349}}, 283 (2015)], we study the mechanism of skyrmion generation by simulating the dynamics of stripe domains. Our theory for skyrmion generation is based on the fact that there are two half skyrmions attached to the ends of a stripe domain. These half skyrmions move due to the coupling between the skyrmion topological charge and current. As a consequence, the stripe domain is bent or stretched depending on the direction of motion of the half skyrmions. For a large current, skyrmions are created by chopping the stripe domains via strong bending or stretching. Our theory provides an explanation to the experiments and is supported by the new experiments. Furthermore, we predict that skyrmions can also be generated using a Bloch stripe domain under a spin transfer torque which can be realized in B20 compounds.