Finite-temperature stability of skyrmion crystals in frustrated magnets: Role of sixfold anisotropy and uniform spin mode in momentum space

TL;DR

This paper investigates how sixfold anisotropy and uniform spin modes in momentum space influence the finite-temperature stability of skyrmion crystals in frustrated magnets, combining theoretical analysis with Monte Carlo simulations.

Contribution

It identifies key momentum-space features that stabilize skyrmion crystals and demonstrates how anisotropy enhances their thermal stability in a classical Heisenberg model.

Findings

Sixfold anisotropy in momentum space stabilizes skyrmion phases.

Larger anisotropy extends the skyrmion stability region.

Uniform spin mode energy correlates with skyrmion emergence.

Abstract

We study the finite-temperature stability of skyrmion crystals in frustrated magnets by analyzing the momentum-space exchange interaction of a classical Heisenberg model on a triangular lattice. Our analysis identifies two key momentum-space features that play a crucial role in stabilizing the skyrmion crystal phase. The first is the sixfold anisotropy in the momentum-space exchange interaction, which acts as a locking potential favoring triple-$Q$ skyrmion crystals. Monte Carlo simulations reveal that a larger anisotropy tends to enhance the stability region of the skyrmion crystal in the temperature--magnetic-field phase diagram. The second factor is the momentum-space energy related to the uniform spin mode, which correlates with the emergence of the skyrmion crystal phase at finite temperatures. These results provide a further understanding of the stabilization mechanism of the skyrmion crystal phase in frustrated magnets and will be useful for the design of skyrmion-hosting materials.