# Magnon-polarons in cubic collinear Antiferromagnets

## TL;DR

This paper provides a theoretical framework for understanding magnon-polaron excitations in cubic antiferromagnets, demonstrating how hybridization occurs and can be controlled, with a detailed case study on Nickel Oxide.

## Contribution

It introduces a general approach to identify hybridizing magnon and phonon modes and applies it to Nickel Oxide, revealing unique features of antiferromagnetic magnon-polarons.

## Key findings

- Hybridization between magnons and longitudinal phonons in antiferromagnets.
- External magnetic fields can control magnon-polaron hybridization.
- Qualitative analysis matches quantitative results for Nickel Oxide.

## Abstract

We present a theoretical study of excitations formed by hybridization between magnons and phonons - magnon-polarons - in antiferromagnets. We first outline a general approach to determining which magnon and phonon modes can and cannot hybridize in a system thereby addressing the qualitative questions concerning magnon-polaron formation. As a specific and experimentally relevant case, we study Nickel Oxide quantitatively and find perfect agreement with the qualitative analysis, thereby highlighting the strength of the former. We find that there are two distinct features of antiferromagnetic magnon-polarons which differ from the ferromagnetic ones. First, hybridization between magnons and the longitudinal phonon modes is expected in many cubic antiferromagnetic structures. Second, we find that the very existence of certain hybridizations can be controlled via an external magnetic field, an effect which comes in addition to the ability to move the magnon modes relative to the phonons modes.