Three-dimensional skyrmion states in thin films of cubic helimagnets

TL;DR

This paper demonstrates that three-dimensional skyrmion states in thin cubic helimagnet films are stable and can be described as superpositions of conical and double-twist modulations, revealing the physical mechanism behind their formation.

Contribution

It introduces a detailed 3D model of skyrmions in cubic helimagnets and shows their stability in thin films under various magnetic fields.

Findings

3D skyrmions are modulated along three spatial directions.

3D skyrmion lattices and helicoids are thermodynamically stable.

The structure combines conical modulations and double-twist rotations.

Abstract

A direct three-dimensional minimization of the standard energy functional shows that in thin films of cubic helimagnets chiral skyrmions are modulated along three spatial directions. The structure of such 3D skyrmions can be thought of as a superposition of conical modulations along the skyrmion axis and double-twist rotation in the perpendicular plane. Numerical solutions for chiral modulations demonstrate that 3D skyrmion lattices and helicoids are thermodynamically stable in a broad range of applied magnetic fields. Our results disclose a basic physical mechanism underlying the formation of skyrmion states recently observed in nanolayers of cubic helimagnets.