Mapping the magnetic exchange interactions from first principles: Anisotropy anomaly and application to Fe, Ni, and Co

TL;DR

This paper investigates the mapping of magnetic exchange interactions from first principles, revealing an anisotropy anomaly caused by high-order spin interactions, with applications to Fe, Ni, and Co.

Contribution

It identifies a spurious anisotropy in standard mapping methods due to high-order spin interactions and proposes a way to evaluate non-bilinear contributions.

Findings

Spurious anisotropy arises in the mapping process.

High-order spin interactions influence magnetic anisotropy.

Application to Fe, Ni, and Co demonstrates the method's relevance.

Abstract

Mapping the magnetic exchange interactions from model Hamiltonian to density functional theory is a crucial step in multi-scale modeling calculations. Considering the usual magnetic force theorem but with arbitrary rotational angles of the spin moments, a spurious anisotropy in the standard mapping procedure is shown to occur provided by bilinear-like contributions of high order spin interactions. The evaluation of this anisotropy gives a hint on the strength of non-bilinear terms characterizing the system under investigation.