Electric-Polarization Probe of the Magnon Orbital Moment Current in Altermagnet

TL;DR

This paper develops a theoretical framework to electrically detect magnon orbital moment currents in altermagnets, revealing measurable voltages and advancing spintronics and orbitronics technologies.

Contribution

It introduces a novel theory for magnon orbital moment transport and proposes an electrical detection method in altermagnets, a new approach in the field.

Findings

Identifies a measurable transverse voltage of ~0.4 μV in altermagnets due to magnon orbital currents.

Establishes a concrete electrical detection scheme for magnon orbital transport.

Highlights magnons as low-dissipation information carriers for orbitronics.

Abstract

Efficient transport of spin and orbital moments, and their electrical detection, are among the main challenges in spintronics and orbitronics. In magnetic insulators, these currents are mediated by magnons. In addition to carrying spin and orbital moment, the orbital motion of a magnon combined with its magnetic moment, generates an effective electric dipole moment. Here, we develop a theoretical framework for Seebeck- and Nernst-type transport of the magnon orbital moment (MOM) and its associated electric dipole moment (EDM). We identify a Drude-like scattering contribution and an intrinsic component governed by the generalized Berry curvatures of magnon bands. We show that a measurable transverse voltage generated by the EDM current provides a direct electrical detection scheme for magnon orbital transport. Applying our theory to an hexagonal altermagnet, we obtain an experimentally accessible voltage of approximately $0.4~\mu$V. Our results establish a concrete electrical probe of magnon orbital transport and highlight magnons as potential low-dissipation information carriers for orbitronics.