# Magnetic Skyrmion State in Janus Monolayers of Chromium Trihalides Cr(I,X)3

## TL;DR

This paper proposes creating Janus monolayers of chromium trihalides to induce Dzyaloshinskii-Moriya interactions, enabling the formation of magnetic skyrmions in two-dimensional materials, which are promising for future nano-scale devices.

## Contribution

It introduces a novel fabrication approach for Janus monolayers of Cr(I,X)3 that exhibit skyrmionic states due to engineered DMI, advancing 2D magnetic skyrmion research.

## Key findings

- Cr(I,Br)3 hosts intrinsic skyrmionic states.
- Cr(I,Cl)3 exhibits magnetic-field-induced skyrmions.
- Janus monolayers enable DMI and skyrmion formation in 2D magnets.

## Abstract

Magnetic skyrmions are nano-scale spin structures that are promising for ultra-dense memory and logic devices. Recent progresses in two-dimensional magnets encourage the idea to realize skyrmionic states in freestanding monolayers. However, monolayers such as CrI3 lack Dzyaloshinskii-Moriya interactions (DMI) and thus do not naturally exhibit skyrmions but rather a ferromagnetic state. Here we propose the fabrication of Cr(I,X)3 Janus monolayers, in which the Cr atoms are covalently bonded to the underlying I ions and top-layer Br or Cl atoms. By performing first-principles calculations and Monte-Carlo simulations, we identify strong enough DMI, which leads to not only helical cycloid phases, but also to intrinsic skyrmionic states in Cr(I,Br)3 and magnetic-field-induced skyrmions in Cr(I,Cl)3.