Magnon-Driven Anomalous Hall Effect in Altermagnets

TL;DR

This paper introduces a novel magnon-driven anomalous Hall effect in altermagnets, where chiral magnons influence electronic motion, enabling Hall effects even when static effects are symmetry-forbidden.

Contribution

It demonstrates a new mechanism for the anomalous Hall effect driven by magnons in altermagnets, distinct from traditional static effects, with potential for controlling electronic chirality.

Findings

Hall conductivity depends on Nél order precession chirality

Effect exists even when static anomalous Hall effect is forbidden

Model exemplifies in altermagnet CrSb with no static Hall effect

Abstract

We propose a magnon-driven anomalous Hall effect in altermagnets, arising from the coupling between coherently excited chiral magnons and chiral electronic motion. Using density-matrix perturbation theory and symmetry analysis, we show that the resulting Hall conductivity is solely determined by the chiralithy of the N\'eel-order precession, in sharp contrast to the anomalous Hall effect from the equilibrium N\'eel order. It then has distinct symmetry requirements from the latter and can exist even when the latter is forbidden by symmetry. The magnon-driven anomalous Hall effect is exemplified in a minimal lattice model with the same symmetry of the altermagnet CrSb, which hosts no static anomalous Hall effect. Our results reveal a direct interplay between chiral magnons and chiral electronic motion, paving the way of probing magnon chirality and to control electronic chirality through magnons.