Optically Driven Orbital Hall Transport in Floquet Odd-Parity Collinear Altermagnets with High Chern Numbers

TL;DR

This paper demonstrates how circularly polarized light can induce and control high-Chern-number quantum anomalous Hall effects and orbital Hall effects in two-dimensional collinear altermagnets, with potential applications in topological spintronics and orbitronics.

Contribution

It introduces a method to optically induce and manipulate topological phases with high Chern numbers in altermagnets using Floquet engineering and symmetry analysis.

Findings

Floquet engineering induces $f$-wave odd-parity altermagnetism.

Tunable QAHE with Chern numbers up to $ ext{±}8$ is achieved.

VSi$_2$N$_4$ is identified as a feasible platform for experimental realization.

Abstract

Recent studies have attracted increasing interest in nonrelativistic odd-parity magnetism and its associated topology in collinear altermagnets. Here, based on symmetry analysis and an effective model, we demonstrate that Floquet engineering can induce $f$-wave odd-parity altermagnetism in two-dimensional collinear antiferromagnetic multilayers via the coupling between circularly polarized light (CPL) and layer degrees of freedom. Furthermore, modifying the CPL induces nonequilibrium quantum anomalous Hall effect (QAHE) with tunable Chern numbers up to $C=\pm8$, arising from layer- and valley-dependent band inversions. The induced topological phase transitions provide an efficient means to manipulate the orbital Hall effect (OHE) by redistributing orbital angular momentum. First-principles calculations reveal that experimentally accessible VSi$_2$N$_4$ serves as a viable platform for topological phase diagram of the QAHE and OHE, featuring pronounced trigonal warping. Our findings establish a versatile route toward optically controllable topological phenomena, opening new opportunities for future developments in topological spintronics and orbitronics.