Chiral magnetism in lithium-decorated monolayer CrTe$_{2}$: Interplay between Dzyaloshinskii-Moriya interaction and higher-order interactions

TL;DR

This study investigates the magnetic interactions in lithium-decorated monolayer CrTe₂, revealing the importance of higher-order interactions alongside Dzyaloshinskii-Moriya interactions in shaping chiral spin textures like spirals and skyrmions.

Contribution

The paper introduces a comprehensive first-principles-based spin model for LiCrTe₂, highlighting the role of higher-order interactions in chiral magnetism of 2D materials.

Findings

Ground state is a chiral spin spiral

Labyrinth domains form at zero field

Skyrmions emerge under magnetic field

Abstract

Chiral magnetic states in two-dimensional (2D) layered noncentrosymmetric magnets, which are promising advanced spintronic materials, are usually attributed to Dzyaloshinskii-Moriya interactions (DMI). However, the role of underlying higher-order spin couplings in determining the properties of chiral spin textures has much less reported. In this work, taking the lithium-decorated monolayer CrTe$_{2}$ (monolayer LiCrTe$_{2}$) as an example, we develop a first-principles-based comprehensive spin model constructed by using the symmetry-adapted cluster expansion method. Based on this spin model, we identify the ground state of monolayer LiCrTe$_{2}$ as a chiral spin spiral state, which can further assemble macroscopic chiral labyrinth domains (LD) under zero-field conditions as well as evolve into skyrmions under a finite magnetic field. Moreover, higher-order biquadratic and three-site interactions are identified to be responsible for modulating both the size and the field stability of the spin spiral state. Our study sheds light on complex magnetic couplings in 2D magnets.