Interaction-Driven Altermagnetic Magnon Chiral Splitting

TL;DR

This paper reveals how nonlinear three-wave magnon interactions in altermagnets lead to relativistic chiral splitting, uncovering a new bosonic symmetry-protected mechanism with potential for magnonic device applications.

Contribution

It introduces a novel relativistic chiral splitting mechanism in altermagnets driven by three-wave magnon interactions, expanding understanding of magnon dynamics beyond nonrelativistic regimes.

Findings

Identifies three classes of chiral splitting based on symmetries.

Demonstrates magnon splitting extends into relativistic regimes.

Proposes potential applications in magnonic devices.

Abstract

Nonrelativistic magnon chiral splitting in altermagnets has garnered significant recent attention. In this work, we demonstrate that nonlinear three-wave mixing -- where magnons split or coalesce -- extends this phenomenon into unprecedented relativistic regimes. Employing a bilayer antiferromagnet with Dzyaloshinskii-Moriya interactions, we identify three distinct classes of chiral splitting, each dictated by specific symmetries, such as $C_4T$, $\sigma_v T$, or their combination. This reveals a novel bosonic mechanism for symmetry-protected chiral splitting, capitalizing on the unique ability of magnons to violate particle-number conservation, a feature absent in low-energy fermionic systems. Our findings pave the way for engineering altermagnetic splitting, with potential applications in advanced magnonic devices and deeper insights into magnon dynamics in complex magnetic systems.