Beyond the orbitally-resolved magnetic exchange in CrI$_{3}$ and NiI$_{2}$

TL;DR

This paper develops a comprehensive method to analyze all mechanisms of magnetic exchange in materials, revealing significant orbital contributions in 2D magnetic monolayers CrI3 and NiI2, and generalizing findings to similar systems.

Contribution

The authors introduce a systematic approach to quantify all magnetic exchange mechanisms, surpassing existing theories, and apply it to uncover overlooked orbital contributions in 2D magnetic materials.

Findings

Underrated dx2-y2 orbital contributions are significant in CrI3 and NiI2.

The method reveals all non-zero orbital contributions to magnetic exchange.

Findings are generalized to other d8 and d3 electronic configurations.

Abstract

The pertinent need for microscopic understanding of magnetic exchange motivated us to go beyond the existing theories and develop a systematic method to quantify all possible mechanisms that contribute to magnetic exchange for an arbitrary pair of atoms in a given material. We apply it to the archetypal 2D magnetic monolayers CrI3 and NiI2, to reveal the previously underrated dx2-y2,dx2-y2 contribution as either the leading or the second largest contribution to the total magnetic exchange. We proceed to explore the microscopic mechanisms behind all the non-zero orbital contributions in both CrI3 and NiI2, and generalize the findings to other magnetic monolayers dominated by d8 and d3 electronic configurations of the magnetic atoms.