First-principles theory of the orbital magnetization

TL;DR

This paper presents a first-principles method to compute orbital magnetization in materials using density functional theory, improving accuracy by including interstitial contributions and applying it to molecules and solids.

Contribution

It introduces a novel formula for orbital magnetization in periodic systems and demonstrates its effectiveness in ferromagnetic metals and complex molecules.

Findings

Improved orbital magnetization values for Fe, Co, Ni.

Accurate g-tensor calculations matching linear response results.

Applicable to radicals and defects with heavy atoms.

Abstract

We compute the orbital magnetization in real materials by evaluating a recently discovered formula for periodic systems, within density functional theory. We obtain improved values of the orbital magnetization in the ferromagnetic metals Fe, Co, and Ni, by taking into account the contribution of the interstitial regions neglected so far in literature. We also use the orbital magnetization to compute the EPR $g$-tensor in molecules and solids. The present approach reproduces the $g$-tensor obtained by linear response (LR), when the spin-orbit can be treated as a perturbation. However, it can also be applied to radicals and defects with an orbital-degenerate ground-state or containing heavy atoms, that can not be properly described by LR.