Monte Carlo studies of skyrmion stabilization under geometric confinement and uniaxial strain

TL;DR

This study uses Monte Carlo simulations to explore how geometric confinement and uniaxial strain stabilize skyrmions in nanostructures, revealing mechanisms involving boundary conditions and lattice deformations that extend skyrmion stability.

Contribution

It demonstrates that boundary-imposed zero DMI coupling and tensile strains enhance skyrmion stability, clarifying the underlying mechanisms of confinement effects.

Findings

Confinement stabilizes skyrmions at low magnetic fields.

Tensile strain extends skyrmion phase to lower temperatures.

Simulation results align with experimental observations on Cu2OSeO3.

Abstract

Geometric confinement (GC) of skyrmions in nanodomains plays a crucial role in skyrmion stabilization. This confinement effect decreases the magnetic field necessary for skyrmion formation and is closely related to the applied mechanical stresses. However, the mechanism of GC is unclear and remains controversial. Here, we numerically study the effect of GC on skyrmion stabilization and find that zero Dzyaloshinskii-Moriya interaction (DMI) coupling constants imposed on the boundary surfaces of small thin plates cause confinement effects, stabilizing skyrmions in the low-field region. Moreover, the confined skyrmions are further stabilized by tensile strains parallel to the plate, and the skyrmion phase extends to the low-temperature region. This stabilization occurs due to the bulk anisotropic DMI coupling constant caused by lattice deformations. Our simulation data are qualitatively consistent with reported experimental data on skyrmion stabilization induced by tensile strains applied to a thin plate of the chiral magnet ${\rm Cu_2OSeO_3}$.