Strong coupling of chiral magnons in altermagnets

TL;DR

This paper demonstrates that dipole-dipole interactions in altermagnets induce strong, anisotropic coupling between chiral magnons, revealing unique spectral features absent in conventional antiferromagnets, with implications for quantum magnonic devices.

Contribution

It uncovers the role of dipole-dipole interactions in creating strong, anisotropic magnon coupling in altermagnets, a novel phenomenon not observed in traditional antiferromagnets.

Findings

Dipole-dipole interaction induces strong magnon coupling.

Magnon coupling is highly anisotropic and experimentally observable.

Unique spectral features differentiate altermagnets from conventional antiferromagnets.

Abstract

Altermagnets recently are identified as a new class of magnets that break the time-reversal symmetry without exhibiting net magnetization. The role of the dipole-dipole interaction (DDI) on their dynamical properties however is yet to be addressed. In this work, we show that the DDI can induce the strong coupling between exchange magnons with opposite chiralities in altermagnets, manifesting as a significant level repulsion in the magnon spectrum. Crucially, the predicted magnon-magnon coupling is highly anisotropic, and observable in practical experiments. These exotic features are absent in conventional antiferromagnets. Our findings open a new pathway for quantum magnonic information processing based on altermagnetism.