Efficient Generation of Spin Currents in Altermagnets via Magnon Drag

TL;DR

This paper demonstrates that in altermagnets, a charge current can efficiently generate a transverse magnon spin current through electron-magnon interactions, independent of spin-orbit coupling, with potential applications in spintronics.

Contribution

It reveals a novel mechanism for generating spin currents in altermagnets via magnon drag, expanding the understanding of spin transport without relying on spin-orbit effects.

Findings

Charge current induces transverse magnon spin current.

Magnon dispersion remains unaffected by electron-magnon interaction.

The effect depends on chemical potential and temperature.

Abstract

Altermagnets, a recently identified class of magnetic materials, possess a spin-split Fermi surface that results in the so-called spin splitter effect, enabling the generation of a spin current transverse to the injection direction and whose polarization lies along the N\'eel vector. In this study, we investigate how magnons interact with electrons in an altermagnetic metal. We find that while the electron-magnon interaction does not perturb the magnon dispersion, a charge current flowing in the material can induce a transverse magnon spin current, analogous to the electronic spin splitter effect. This spin current possesses both electronic and magnonic characteristics, i.e., a chemical potential dependence and a strong temperature dependence. This effect realizes the efficient generation of spin currents via magnons without depending on the material's spin-orbit coupling.