题 目：Breakdown of boundary criticality and exotic topological semimetals in PT invariant systems

报告人：吴洪，重庆邮电大学

时 间：2025年6月13日（星期五）上午10:30

地 点：理科楼LE201

邀请人：许东辉

报告摘要：It was recently found that, going beyond the tenfold Altland-Zirnbauer symmetry classes and violating the bulk-boundary correspondence of the usual topological phases, PT-invariant systems support a real Chern insulator with the so-called boundary criticality, which forbids the transition between different orders of topological phases accompanied by the touching of the bulk bands. Here, we find that periodic driving can break the boundary criticality of a PT-invariant system. Upon setting the system free from the boundary criticality, diverse first- and second-order topological phases absent in the static case are found in both the zero and the π/T modes. In contrast to the usual Floquet ones defined on stroboscopic dynamics, our topological phases can only be characterized by the dynamical process of a whole driving period.