Light-induced parity anomaly and topological phase transitions in the antiferromagnetic topological insulator
Phys. Rev. B 114, 065306 – Published 22 July, 2026
DOI: https://doi.org/10.1103/y5s3-ndym
Abstract
The utilization of periodic driving to control nonequilibrium topological phases has garnered increasing attention in condensed matter physics. In this work, within the high-frequency limit of Floquet theory, we investigate the effects of circularly polarized light (CPL) on the topological properties of the antiferromagnetic topological insulator . CPL drives topological phase transitions between the axion insulator (AI) and Chern insulator (CI) phases. These transitions exhibit a strong dependence on the layer number. In addition to the topologically nontrivial CI and topologically trivial normal metal phases, we further identify a topologically nontrivial parity-anomaly state, which emerges at the phase-transition point between the AI and CI phases. At these transition points, gapped and gapless Dirac surface states coexist, and the system manifests a half-quantized Hall conductance, which is a defining signature of the parity anomaly. Moreover, the half-quantized Hall conductance under strong dephasing, as well as its robustness against weak disorder, provides direct evidence for the topological nontriviality of this parity-anomaly state.
