Rectangular and square skyrmion crystals on a centrosymmetric square lattice with easy-axis anisotropy

TL;DR

This study theoretically demonstrates the formation of rectangular and square skyrmion crystals on a centrosymmetric square lattice driven by magnetic anisotropy and higher harmonic interactions, offering insights for new skyrmion materials.

Contribution

It reveals how competing interactions and higher harmonic wave vectors stabilize novel rectangular and square skyrmion crystals on a centrosymmetric lattice.

Findings

Rectangular and square skyrmion crystals are stabilized by higher harmonic interactions.

Skyrmion cores align in rectangular or square lattice arrangements.

Results suggest potential for discovering new skyrmion-hosting materials.

Abstract

We report our theoretical results on the emergence of rectangular- and square-shaped magnetic skyrmion crystals on a centrosymmetric square lattice with magnetic anisotropy. By performing the simulated annealing for a frustrated spin model with an easy-axis single-ion anisotropy on a square lattice, we find that a competition of the interactions in momentum space gives rise to the formation of two skyrmion crystals, where the skyrmion cores are aligned in a rectangle- or square-lattice way. Especially, the interactions at the higher harmonic wave vectors play an important role in stabilizing the square/rectangular skyrmion crystals. Our results provide a reference to explore further skyrmion-hosting materials in centrosymmetric tetragonal systems.