Skyrmions in 2D chiral magnets with noncollinear ground states stabilized by higher-order interactions

TL;DR

This paper predicts and demonstrates the existence of unconventional skyrmions in noncollinear magnetic materials stabilized by higher-order interactions, using first-principles and atomistic simulations, with potential applications in spintronics.

Contribution

It introduces a new class of skyrmions in noncollinear magnets stabilized by four-spin exchange interactions, expanding the understanding of skyrmion stability and formation.

Findings

Noncollinear ground states can be stabilized in Rh/Co and Pd/Co bilayers.

Unconventional skyrmion lattices and isolated skyrmions can emerge in these systems.

Metastable skyrmions are protected by large energy barriers, making them experimentally observable.

Abstract

Magnetic skyrmions are intriguing topological spin textures that have attracted great attention due to their potential for future spintronic devices. Skyrmions have so far been explored in different magnetic materials, such as ferromagnets, antiferromagnets, and ferrimagnets. Here, we propose a new type of unconventional skyrmions stabilized in noncollinear magnets. Using first-principles calculations and atomistic spin simulations, we demonstrate that a noncollinear ground state can be stabilized in Rh/Co and Pd/Co atomic bilayers on the Re(0001) surface by four spin exchange interactions, although Co -- a material often used in applications -- is a prototypical ferromagnet with strong pairwise exchange interaction. We further show that unconventional skyrmion lattices and isolated skyrmions can emerge on this noncollinear magnetic background. Transition-state theory calculations reveal that these metastable skyrmions are protected by large energy barriers, suggesting that they could be observed in experiments. These unconventional types of skyrmions in noncollinear magnets might open new possibilities for topological spin transport or magnet-superconductor hybrid systems.