Skyrmion Molecular Crystals and Superlattices on Triangular Substrates

TL;DR

This paper demonstrates the formation of novel skyrmion molecular crystals and superlattices on triangular substrates through atomistic simulations, revealing diverse ordered phases influenced by magnetic field and substrate periodicity.

Contribution

It introduces new skyrmion states on triangular substrates and explores their complex ordered phases, including superlattices with varying skyrmion sizes and shapes.

Findings

Discovery of skyrmion molecular crystals and superlattices.

Identification of diverse ordered phases similar to colloidal crystals.

Skyrmion size and shape variability leads to complex lattice structures.

Abstract

Using atomistic simulations, we show that new types of skyrmion states called skyrmion molecular crystals and skyrmion superlattices can be realized on triangular substrates when there are two or three skyrmions per substrate minimum. We find that as a function of the magnetic field and substrate periodicity, a remarkably wide variety of ordered phases appear similar to those found in colloidal or Wigner molecular crystals, including ferromagnetic and herringbone states. The ability of the skyrmions to annihilate, deform, and change size gives rise to a variety of superlattice states in which a mixture of different skyrmion sizes and shapes produces bipartate or more complex lattice structures. Our results are relevant for skyrmions on structured triangular substrates, in magnetic arrays, or skyrmions in moire materials.