Chiral magnetism in lithium-decorated monolayer CrTe2: Interplay between Dzyaloshinskii-Moriya interaction and higher-order interactions

Chiral magnetic states in two-dimensional (2D) layered noncentrosymmetric magnets, which are promising advanced spintronic materials, are usually attributed to Dzyaloshinskii-Moriya interactions (DMIs). However, the role of underlying higher-order spin couplings in determining the properties of chiral spin textures has been much less studied. In this work, taking the lithium-decorated monolayer CrTe2 (monolayer LiCrTe2) 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 LiCrTe2 as a chiral spin spiral state, which can further assemble macroscopic chiral labyrinth domains 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.