Symmetry-Protected Localized States at Defects in Non-Hermitian Systems




Journal Title

Journal ISSN

Volume Title


American Physical Society


Understanding how local potentials affect system eigenmodes is crucial for experimental studies of nontrivial bulk topology. Recent studies have discovered many exotic and highly nontrivial topological states in non-Hermitian systems. As such, it would be interesting to see how non-Hermitian systems respond to local perturbations. In this work we consider chiral and particle-hole-symmetric non-Hermitian systems on a bipartite lattice, including the Su-Schrieer-Heeger model and photonic graphene, and find that a disordered local potential could induce bound states evolving from the bulk. When the local potential on a single site becomes infinite, which renders a lattice vacancy, chiral-symmetry-protected zero-energy mode and particle-hole-symmetry-protected bound states with purely imaginary eigenvalues emerge near the vacancy. These modes are robust against any symmetry-preserved perturbations. Our work generalizes the symmetry-protected localized states to non-Hermitian systems. © 2019 American Physical Society.



Eigenvalues, Eigenfunctions, Particles (Nuclear physics)—Chirality, Topology, Eigenfunctions, Hermitian structures

NSFC through Grant No. 11504285, the Scientific Research Program Funded by Natural Science Basic Research Plan in Shaanxi Province of China (Programs No. 2018JQ1058 and No. 2019JM-001), the Scientific Research Program Funded by Shaanxi Provincial Education Department through Grant No. 18JK0397, and a scholarship from China Scholarship Council (Program No. 201708615072).


©2019 American Physical Society