Topologically stable bimerons and skyrmions in vanadium dichalcogenide Janus monolayers

TL;DR

This paper explores the magnetic phases of Janus monolayers of vanadium dichalcogenides, revealing their ability to host stable topological magnetic textures like skyrmions and bimerons at near-room temperatures.

Contribution

It provides first-principles calculations and atomistic simulations showing how Dzyaloshinskii-Moriya interactions stabilize topological textures in these 2D materials.

Findings

DMI is strong enough to stabilize chiral textures.

VSeTe monolayer hosts bimeron and skyrmion lattices under different fields.

VSSe monolayer supports skyrmion lattices at room temperature.

Abstract

We investigate the magnetic phase diagram of 1T-vanadium dichalcogenide monolayers in Janus configuration (VSeTe, VSSe, and VSTe) from first principles. The magnetic exchange, magnetocrystalline anisotropy and Dzyaloshinskii-Moriya interaction (DMI) are computed using density functional theory calculations, while the temperature- and field-dependent magnetic phase diagram is simulated using large-scale atomistic spin modeling in the presence of thermal fluctuations. The boundaries between magnetic ordered phases and paramagnetic phases are determined by cross-analyzing the average topological charge with the magnetic susceptibility and its derivatives. We find that in such Janus monolayers, DMI is large enough to stabilize non-trivial chiral textures. In VSeTe monolayer, an asymmetrical bimeron lattice state is stabilized for in-plane field configuration whereas skyrmion lattice is formed for out-of-plane field configuration. In VSSe monolayer, a skyrmion lattice is stabilized for out-of-plane field configuration. This study demonstrates that non-centrosymmetric van der Waals magnetic monolayers can support topological textures close to room temperature.