Spin waves in antiferromagnetically coupled bilayers of transition-metal dichalcogenides with Dzialoshinskii-Moriya interaction

TL;DR

This paper theoretically analyzes spin wave behavior in bilayer transition-metal dichalcogenides with Dzialoshinskii-Moriya interaction, considering external symmetry-breaking effects and in-plane anisotropy, using advanced spin wave theory.

Contribution

It introduces a theoretical framework for understanding spin waves in bilayer 2D materials with Dzialoshinskii-Moriya interaction and external symmetry-breaking influences.

Findings

Spin wave spectra depend on external symmetry-breaking factors.

The analysis confirms stability of collinear spin ground state under certain conditions.

Theoretical predictions can guide experimental investigations of spin dynamics.

Abstract

In this paper we analyze spin waves in bilayers of two-dimensional van der Waals materials, like Vanadium based dichalcogenides, VX$_2$ (X=S, Se, Te) and other materials of similar symmetry. We assume that the materials exhibit Dzialoshinskii- Moriya interaction and in-plane easy-axis magnetic anisotropy due to symmetry breaking induced externally (eg, by strain, gate voltage, proximity effects to an appropriate substrate/oberlayer, etc). The considerations are limited to a collinear spin ground state, stabilized by a sufficiently strong in-plane magnetic anisotropy. The theoretical analysis is performed within the general spin wave theory based on the Hollstein-Primakoff-Bogolubov transformation.