Chiral-Damping-Enhanced Magnon Transmission

TL;DR

This paper demonstrates that chiral non-Hermitian dynamics can turn damping from a detrimental factor into a beneficial feature, enabling unidirectional magnon transmission and potential magnonic device applications.

Contribution

It introduces a novel approach where chiral damping in ferromagnetic heterostructures enhances magnon transmission by enabling unidirectional transparency.

Findings

Magnon wave packets can be unidirectionally transmitted through potential barriers.

Chiral damping induces asymmetric scattering properties.

Passive magnon gates can utilize damping for functional advantages.

Abstract

The inevitable Gilbert damping in magnetization dynamics is usually regarded as detrimental to spin transport. Here we apply a general feature of chiral non-Hermitian dynamics to a ferromagnetic-insulator--normal-metal heterostructure to show that the strong momentum dependence and chirality of the eddy-current-induced damping also causes beneficial scattering properties: A potential barrier that reflects magnon wave packets becomes unidirectionally transparent in the presence of a metallic cap layer. Passive magnon gates that turn presumably harmful dissipation into useful functionalities should be useful for future quantum magnonic devices.