Goodenough-Kanamori-Anderson rules in 2D magnet: A chemical trend in MCl2 with M=V, Mn, and Ni

TL;DR

This study uses density-functional theory to explore magnetic behaviors in monolayer MCl2 compounds, revealing a chemical trend in magnetic ground states explained by Goodenough-Kanamori-Anderson rules.

Contribution

It demonstrates the application of these rules to 2D magnets and clarifies the microscopic mechanisms behind their magnetic interactions.

Findings

VCl2 and MnCl2 are antiferromagnetic

NiCl2 is ferromagnetic

Magnetic interactions are explained by superexchange and direct exchange mechanisms.

Abstract

Density-functional-theory calculations were performed to investigate the magnetism in a series of triangular-lattice monolayer MCl2 (M=V, Mn, and Ni). The magnetic stability manifests a distinct chemical trend; VCl2 and MnCl2 show the antiferromagnetic ground states and NiCl2 shows the ferromagnetic ground state. The microscopic mechanism behind the magnetic interaction is explained by the so-called Goodenough-Kanamori-Anderson rules and by the virtual-hopping process through the hopping integrals between the 3d-orbital maximally localized Wannier functions. Our result highlights the role of the direct exchange interaction and the superexchange interaction in the magnetic stabilization in two-dimensional magnets.