Antiferromagnetic magnons and local anisotropy: dynamical mean-field study

TL;DR

This study uses dynamical mean-field theory to explore how anisotropy and spin-orbit coupling influence antiferromagnetic magnons in multi-orbital Hubbard models across different lattice structures.

Contribution

It provides a comprehensive analysis of anisotropy effects on antiferromagnetic magnons using DMFT in various orbital and lattice configurations, including spin-orbit coupling.

Findings

Magnons and ordered states are sensitive to SU(2) symmetry breaking.

Magnetic excitations follow spin-wave theory predictions.

Anisotropy tuning affects the magnetic excitation spectrum.

Abstract

We present a dynamical mean-field study of antiferromagnetic magnons in one-, two- and three-orbital Hubbard model of square and bcc cubic lattice at intermediate coupling strength. Weinvestigate the effect of anisotropy introduced by an external magnetic field or single-ion anisotropy.For the latter we tune continuously between the easy-axis and easy-plane models. We also analyzea model with spin-orbit coupling in cubic site-symmetry setting. The ordered states as well as themagnetic excitations are sensitive to even a small breaking ofSU(2)symmetry of the model andfollow the expectations of spin-wave theory as well as general symmetry considerations.