Skyrmion formation in Ni-based Janus dihalide monolayers: Interplay between magnetic frustration and Dzyaloshinskii-Moriya interaction

TL;DR

This paper develops a comprehensive theoretical framework combining first-principles calculations and atomistic simulations to explore magnetic phases and skyrmion formation in Ni-based Janus monolayers, highlighting the roles of magnetic frustration and Dzyaloshinskii-Moriya interactions.

Contribution

It introduces a detailed model for magnetic interactions in Ni-dihalide Janus monolayers, revealing the interplay between frustration and Dzyaloshinskii-Moriya interactions leading to skyrmion formation.

Findings

Ni-dihalide Janus monolayers are stable according to phonon and molecular dynamics simulations.

Magnetic frustration and Dzyaloshinskii-Moriya interactions vary across different monolayers.

Skyrmions emerge due to the interplay of competing magnetic interactions.

Abstract

We present a comprehensive theory of the magnetic phases in monolayer nickel-based Janus dihalides (NiIBr, NiICl, NiBrCl) through a combination of first-principles calculations and atomistic simulations. Phonon band structure calculations and finite temperature molecular dynamics simulations show that Ni-dihalide Janus monolayers are stable. The parameters of the interacting spin Hamiltonian extracted from ab initio calculations show that nickel-dihalide Janus monolayers exhibit varying degrees of magnetic frustration together with a large Dzyaloshinskii-Moriya interaction due to their inherent inversion symmetry breaking. The atomistic simulations reveal a delicate interplay between these two competing magnetic interactions in giving rise to skyrmion formation.