Single-layer Skyrmions in a van der Waals Antiferromagnet

TL;DR

This paper theoretically investigates single-layer antiferromagnetic skyrmions in Fe-doped NiBr₂, revealing their existence in various magnetic phases and how their dynamics are affected by magnetic state transitions.

Contribution

It demonstrates the existence of single-layer AFM skyrmions in a van der Waals magnet and analyzes their behavior across different magnetic phases.

Findings

AFM interlayer interactions suppress skyrmion lattices

Single-layer skyrmions with topological charges 1, 2, and 3 are confined to a single layer

Skyrmion dynamics change drastically at phase transitions

Abstract

Transition metal halides are quasi-two-dimensional van der Waals magnets that can potentially host antiferromagnetic (AFM) skyrmions induced by competing exchange interactions. We study theoretically magnetic states of Fe-doped NiBr$_2$ using spin interactions obtained by fitting experimental data. We find that AFM interlayer interactions suppress skyrmion lattices but allow for skyrmions with topological charges $1,2$ and $3$ confined to a single magnetic layer. These single-layer skyrmions exist in three different magnetic phases and their dynamics changes drastically at the transition from a uniform to a non-collinear modulated state.