Electronic structure and finite temperature magnetism of yttrium iron garnet

TL;DR

This paper presents an ab initio study of yttrium iron garnet's electronic structure and magnetic properties using advanced quantum methods, accurately predicting its magnon spectrum and thermodynamic behavior.

Contribution

It introduces a fully ab initio approach combining quasiparticle self-consistent GW and spin dynamics to model complex magnetic insulators like yttrium iron garnet.

Findings

Favorable agreement with experimental Curie temperature

Accurate magnon spectrum prediction

Detailed electronic structure characterization

Abstract

Yttrium iron garnet is a complex ferrimagnetic insulator with 20 magnon modes which is used extensively in fundamental experimental studies of magnetisation dynamics. As a transition metal oxide with moderate gap (2.8 eV), yttrium iron garnet requires a careful treatment of electronic correlation. We have applied quasiparticle self-consistent GW to provide a fully ab initio description of the electronic structure and resulting magnetic properties, including the parameterisation of a Heisenberg model for magnetic exchange interactions. Subsequent spin dynamical modelling with quantum statistics extends our description to the magnon spectrum and thermodynamic properties such as the Curie temperature, finding favourable agreement with experimental measurements. This work provides a snapshot of the state-of-the art in modelling of complex magnetic insulators.