An Effective Field Theory of Magneto-Elasticity

TL;DR

This paper develops a comprehensive effective field theory for magnon-phonon interactions in magnetic insulators, incorporating symmetry-breaking effects, and provides tools for first-principles analysis of magneto-elastic phenomena.

Contribution

It introduces a novel effective field theory framework for magneto-elastic interactions, extending existing models to include all orders of fields and symmetry-breaking effects.

Findings

Derived generalized equations of motion for magnon-phonon systems.

Included Zeeman and Dzyaloshinsky-Moriya interactions in the theory.

Calculated magnon decay width into phonons at leading order.

Abstract

We utilize the coset construction to derive the effective field theory of magnon-phonon interactions in (anti)-ferromagnetic and ferrimagnetic insulating materials. The action is used to calculate the equations of motion which generalize the Landau-Lifshitz and stress equations to allow for magneto-acoustic couplings to all orders in the fields at lowest order in the derivative expansion. We also include the symmetry breaking effects due to Zeeman, and Dzyaloshinsky-Moriya interactions. This effective theory is a toolbox for the study of magneto-elastic phenomena from first principles. As an example we use this theory to calculate the leading order contribution to the magnon decay width due to its the decay into phonons.