Dzyaloshinskii-Moriya Induced Topological Magnon-Phonon Hybridization in 2D Antiferromagnetic Insulators with Tunable Chern Numbers

TL;DR

This paper theoretically explores topological magnon-phonon hybrid excitations in 2D antiferromagnets, revealing tunable Chern numbers and potential experimental signatures like thermal and valley Hall effects for spin caloritronics applications.

Contribution

It introduces a model for magnon-phonon hybridization with Dzyaloshinskii-Moriya interaction, showing tunable topological properties in 2D antiferromagnetic insulators.

Findings

Berry curvature around anti-crossing rings induces non-trivial Chern numbers.

Chern numbers can be manipulated by magnetic field orientation and strength.

Thermal Hall conductivity reflects the topological magnon-polaron bands.

Abstract

We theoretically study magnon-phonon hybrid excitations (magnon-polarons) in two-dimensional antiferromagnets on a honeycomb lattice. With an in-plane Dzyaloshinskii-Moriya interaction (DMI) allowed from mirror symmetry breaking from phonons, we find non-trivial Berry curvature around the anti-crossing rings among magnon and both optical and acoustic phonon bands, which gives rise to finite Chern numbers. We show that the Chern numbers of the magnon-polaron bands can be manipulated by changing the magnetic field direction or strength. We evaluate the thermal Hall conductivity reflecting the non-trivial Berry curvatures of magnon-polarons and propose a valley Hall effect resulting from spin-induced chiral phonons as a possible experimental signature. Our study complements prior work on magnon-phonon hybridized systems without optical phonons and suggests possible applications in spin caloritronics with topological magnons and chiral phonons.