Light-Induced Topological Phase Transitions and Anomalous Thermal Transport in d-Wave Altermagnets

TL;DR

This paper explores how linearly polarized light induces topological phase transitions and affects thermal transport in a two-dimensional d-wave altermagnetic topological insulator, revealing spin-selective topological changes and quantized responses.

Contribution

It introduces a novel mechanism for light-induced topological phase transitions in altermagnets, with analytical formulas for Berry curvature and insights into thermal transport behavior.

Findings

Linearly polarized light breaks spin symmetry, enabling spin-selective topological transitions.

Quantized electrical and thermal Hall responses obey the anomalous Wiedemann Franz law.

Transport coefficients depend on the polarization angle, reversing sign under orthogonal rotation.

Abstract

We study intrinsic thermal transport and Floquet-engineered topology in a two-dimensional d wave altermagnetic topological insulator powered by linearly polarized light. We analyze the anomalous Hall, Nernst, and thermal Hall conductivities, as well as their spin-resolved equivalents, and develop closed-form formulas for the Berry curvature using an analytically calculated high-frequency effective Hamiltonian. We demonstrate that linearly polarized light, in contrast to conventional antiferromagnets, breaks the symmetry connecting spin sectors in altermagnets, allowing a series of spin-selective topological phase transitions from a quantum spin Hall state to a spin-polarized Chern insulator and finally to a trivial phase. The Nernst response shows substantial thermal activation and significant sensitivity to the gap size in the Chern domain, but both the electrical and thermal Hall responses become quantized and meet the anomalous Wiedemann Franz law. Every anomalous transport coefficient exhibits a distinctive d wave dependence on the polarization angle, reversing sign under orthogonal rotation and vanishing at symmetry-restoring directions. Our findings show a path to all-optical regulation of topological and caloritronic responses beyond traditional magnetic systems and establish thermal transport as a sensitive probe of altermagnetic order.