First-principles Study of Non-Collinear Spin Fluctuations Using Self-adaptive Spin-constrained Method

TL;DR

This paper introduces a self-adaptive spin-constrained density functional theory method to accurately simulate non-collinear spin fluctuations and their effects on electronic and lattice properties in magnetic materials.

Contribution

It presents a novel, versatile formalism that captures complex spin fluctuations and coupling effects, advancing first-principles simulations of magnetic phenomena.

Findings

Potential energy surface for Fe includes longitudinal and transverse magnetization variations.

Identifies coupling between magnetic moments and electronic/lattice degrees of freedom.

Analyzes magnetic interactions, band structures, and phonons in excited CrI3 configurations.

Abstract

Spin fluctuations have a substantial influence on the electron and lattice behaviors in magnetic materials, which, however, is difficult to be tracked properly by prevalent first-principles methods. We propose a versatile self-adaptive spin-constrained density functional theory formalism. Applying it to the simulation of itinerant ferromagnetic Fe, we present the potential energy surface comprising longitudinal and transverse variations of magnetization. Moreover, this method enables us to identify the delicate coupling between the magnetic moments and other degrees of freedom by following energy variation. As manifestations, magnetic interaction, electronic band structure, and phonon dispersion curves are illustrated for single-layered CrI$_3$ with excited magnetic configuration. All the above information can be obtained not only for spin fluctuations but also for non-collinear spin configurations with arbitrarily modulations; thus, it holds promise for future applications in condensed-matter physics research.