Skyrmion-Antiskyrmion pair creation by in-plane currents

TL;DR

This paper investigates how in-plane electric currents can generate skyrmion-antiskyrmion pairs in magnetic materials, revealing the underlying physics and potential for controlled skyrmion creation in spintronic applications.

Contribution

It derives a skyrmion equation of motion showing how spin-polarized currents induce pair creation, supported by numerical simulations demonstrating the process.

Findings

Currents can create skyrmion-antiskyrmion pairs without violating topological protection.

On a lattice, antiskyrmions are annihilated, altering the total skyrmion number.

The study provides criteria for pair creation and control of skyrmions.

Abstract

Magnetic skyrmions can be considered as topologically protected localized vortex-like spin textures. Due to their stability, their small size, and the possibility to move them by low electric currents they are promising candidates for spintronic devices. Without violating topological protection, it is possible to create skyrmion-antiskyrmion pairs, as long as the total charge remains unchanged. We derive a skyrmion equation of motion which reveals how spin-polarized charge currents create skyrmion-antiskyrmion pairs. It allows to identify general prerequisites for the pair creation process. We corroborate these general principles by numerical simulations. On a lattice, where topological protection becomes imperfect, the antiskyrmion partner of the pairs is annihilated and only the skyrmion survives. This eventually changes the total skyrmion number and yields a new way of creating and controlling skyrmions.