Berry curvature in magnon-phonon hybrid systems

TL;DR

This paper theoretically investigates the Berry curvature in magnon-phonon hybrid systems, revealing anisotropic textures and divergences influenced by spin-orbit and dipolar interactions, with implications for yttrium iron garnet.

Contribution

It introduces a comprehensive theoretical framework for Berry curvature in magnon-phonon systems considering both spin-orbit and dipolar interactions, highlighting gapless points and anisotropic effects.

Findings

Gapless points form loops in dispersion relations.

Berry curvature exhibits anisotropic textures and divergences.

Realistic estimates for yttrium iron garnet show significant anomalous velocity effects.

Abstract

We theoretically study the Berry curvature of the magnon induced by the hybridization with the acoustic phonons via the spin-orbit and dipolar interactions. We first discuss the magnon-phonon hybridization via the dipolar interaction, and show that the dispersions have gapless points in momentum space, some of which form a loop. Next, when both spin-orbit and dipolar interactions are considered, we show anisotropic texture of the Berry curvature and its divergence with and without gap-closing. Realistic evaluation of the consequent anomalous velocity is given for yttrium iron garnet.