Exceptional second-order topological insulators
Abstract
Point-gap topological phases of non-Hermitian systems exhibit exotic boundary states that have no counterparts in Hermitian systems. Here, we develop classification of second-order point-gap topological phases protected by reflection symmetry. Based on this classification, we propose exceptional second-order topological insulators, exhibiting second-order boundary states stabilized by point-gap topology. As an illustrative example, we uncover a two-dimensional exceptional second-order topological insulator with point-gapless corner states. Furthermore, we identify a three-dimensional exceptional second-order topological insulator that features hinge states with isolated exceptional points, representing second-order topological phases intrinsic to non-Hermitian systems. Our work enlarges the family of point-gap topological phases in non-Hermitian systems.
Cite
@article{arxiv.2411.06898,
title = {Exceptional second-order topological insulators},
author = {Yutaro Tanaka and Daichi Nakamura and Ryo Okugawa and Kohei Kawabata},
journal= {arXiv preprint arXiv:2411.06898},
year = {2025}
}
Comments
30 pages, 13 figures