Converting $PT$-Symmetric Topological Classes by Floquet Engineering

Abstract:Going beyond the conventional classification rule of Altland-Zirnbauer symmetry classes, $PT$ symmetric topological phases are classified by $(PT)^2=1$ or $-1$. The interconversion between the two $PT$-symmetric topological classes is generally difficult due to the constraint of $(PT)^2$. Here, we propose a scheme to control and interconvert the $PT$-symmetric topological classes by Floquet engineering. We find that it is the breakdown of the $\mathbb{Z}_2$ gauge, induced by the $\pi$ phase difference between different hopping rates, by the periodic driving that leads to such an interconversion. Relaxing the system from the constraint of $(PT)^2$, rich exotic topological phases, e.g., the coexisting $PT$-symmetric first-order real Chern insulator and second-order topological insulators not only in different quasienergy gaps, but also in one single gap, are generated. In contrast to conventional Floquet topological phases, our result provides a way to realize exotic topological phases without changing symmetries. It enriches the family of topological phases and gives an insightful guidance for the development of multifunctional quantum devices.

Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Quantum Physics (quant-ph)

arXiv:2504.14846 [cond-mat.mes-hall]

(or arXiv:2504.14846v2 [cond-mat.mes-hall] for this version)

https://doi.org/10.48550/arXiv.2504.14846 Focus to learn more arXiv-issued DOI via DataCite

2026 New J. Phys. 28 083502

https://doi.org/10.1088/1367-2630/ae8b17 Focus to learn more DOI(s) linking to related resources

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