High-spin orbital interactions across van der Waals gaps controlling the interlayer ferromagnetism in van der Waals ferromagnets

TL;DR

This paper investigates the role of high-spin orbital interactions across van der Waals gaps in determining the interlayer ferromagnetism of various van der Waals ferromagnets, revealing key mechanisms that explain their magnetic behaviors.

Contribution

It identifies the specific high-spin orbital interactions responsible for interlayer ferromagnetism in different van der Waals ferromagnets, providing a unified understanding of their magnetic coupling mechanisms.

Findings

High-spin two-orbital two-electron destabilization governs Fe3-xGeTe2, Cr2Ge2Te6, and CrI3.

High-spin four-orbital two-electron stabilization explains VI3 ferromagnetism.

Orbital interactions elucidate previously puzzling magnetic observations.

Abstract

We examined what interactions control the sign and strength of the interlayer coupling in van der Waals ferromagnets such as Fe3-xGeTe2, Cr2Ge2Te6, CrI3 and VI3, to find that high-spin orbital interaction across the van der Waals gaps are a key to understanding their ferromagnetism. Interlayer ferromagnetic coupling in Fe3-xGeTe2 Cr2Ge2Te6, and CrI3 is governed by the high-spin two-orbital two-electron destabilization, but that in VI3 by the high-spin four-orbital two-electron stabilization. These interactions explain a number of seemingly puzzling observations in van der Waals fer-romagnets.