# Very large Dzyaloshinskii-Moriya interaction in two-dimensional Janus manganese dichalcogenides and its application to realize skyrmion states

## TL;DR

This paper demonstrates significant Dzyaloshinskii-Moriya interactions in Janus manganese dichalcogenide monolayers, enabling the formation of skyrmion states at low temperatures, which could lead to novel 2D magnetic devices.

## Contribution

First-principles calculations reveal large DMI in Janus MnXY monolayers, enabling skyrmion states and expanding 2D magnetic material functionalities.

## Key findings

- DMI amplitudes in MnSeTe and MnSTe are comparable to advanced heterostructures.
- Skyrmion states can be stabilized in these monolayers under magnetic fields.
- Skyrmion states fluctuate above 50 K, indicating potential for room-temperature applications.

## Abstract

The Dzyaloshinskii-Moriya interaction (DMI), which only exists in noncentrosymmetric systems, is responsible for the formation of exotic chiral magnetic states. The absence of DMI in most two-dimensional (2D) magnetic materials is due to their intrinsic inversion symmetry. Here, using first-principles calculations, we demonstrate that significant DMI can be obtained in a series of Janus monolayers of manganese dichalcogenides MnXY in which the difference between X and Y on the opposites sides of Mn breaks the inversion symmetry. In particular, the DMI amplitudes of MnSeTe and MnSTe are comparable to those of state-of-the-art ferromagnet/heavy metal (FM/HM) heterostructures. In addition, by performing Monte Carlo simulations, we find that at low temperatures the ground states of the MnSeTe and MnSTe monolayers can transform from ferromagnetic states with worm-like magnetic domains into the skyrmion states by applying external magnetic field. At increasing temperature, the skyrmion states starts fluctuating above 50 K before an evolution to a completely disordered structure at higher temperature. The present results pave the way for new device concepts utilizing chiral magnetic structures in specially designed 2D ferromagnetic materials.

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Source: https://tomesphere.com/paper/1906.00648