Anomalous thermoelectric and thermal Hall effects in irradiated altermagnets

TL;DR

This paper demonstrates that irradiating a $d$-wave altermagnet with high-frequency light induces a topological phase transition to a Chern insulator, revealing distinctive thermoelectric and thermal Hall effects as signatures of topology.

Contribution

It introduces a method to transform altermagnets into Chern insulators using light and analyzes their anomalous thermoelectric and thermal Hall responses.

Findings

Thermoelectric Hall coefficient shows peaks at band gap boundaries.

Thermal Hall coefficient becomes quantized, indicating topological phase.

Light irradiation induces a Chern insulating phase in altermagnets.

Abstract

We show that a $d$-wave altermagnet can be transformed into a Chern insulator by irradiating it with elliptically polarized light from a high-frequency photon beam. We further explore the intrinsic anomalous thermoelectric and thermal Hall effects in light-irradiated altermagnets. At low temperatures, the thermoelectric Hall coefficient exhibits a linear temperature dependence but vanishes within the energy gap between the conduction and valence bands near the $M$ point. However, it displays pronounced peaks and dips at the gap boundaries near both the $M$ and $\Gamma$ points, suggesting that thermoelectric Hall conductivity is a sensitive probe for these gapped regions. Similarly, the low-temperature thermal Hall coefficient, which also shows a linear temperature dependence, becomes quantized across the bandwidth, reflecting the underlying topological character of the light-induced Chern insulating phase. These results establish thermoelectric and thermal Hall transports as powerful signatures of topology in driven altermagnetic systems.