Hybrid topological magnon-phonon modes in honeycomb and kagome lattices

TL;DR

This paper investigates how magnon-phonon interactions in honeycomb and kagome lattices affect topological properties and thermal Hall conductivity, revealing significant hybridization effects and Berry curvature redistribution.

Contribution

It introduces a detailed analysis of topological magnon-phonon hybridization in honeycomb and kagome lattices, highlighting the impact on Berry curvature and thermal transport.

Findings

Hybridization redistributes Berry curvature among bands.

Topological magnon bands become trivial due to coupling.

Thermal Hall conductivity is significantly affected.

Abstract

Magnons and phonons are two fundamental neutral excitations of magnetically ordered materials which can significantly dominate the low-energy thermal properties. In this work we study the interplay of magnons and phonons in honeycomb and Kagome lattices. When the mirror reflection with respect to the magnetic ordering direction is broken, the symmetry-allowed in-plane Dzyaloshinskii-Moriya (DM) interaction will couple the magnons to the phonons and the magnon-polaron states are formed. Besides, both lattice structures also allow for an out-of-plane DM interaction rendering the uncoupled magnons to be topological. Our aim is to study the interplay of such topological magnons with phonons. We show that the hybridization between magnons and phonons can significantly redistribute the Berry curvature among the bands. Especially, we found that the topological magnon band becomes trivial while the hybridized states at lower energy acquire Berry curvature strongly peaked near the avoided crossings. As such the thermal Hall conductivity of topological magnons shows significant changes due to coupling to the phonons.