Non-Hermitian $C_{NH}=2$ Chern insulator protected by generalized rotational symmetry

Abstract

We propose a non-Hermitian topological system protected by the generalized rotational symmetry which invokes rotation in space and Hermitian conjugation. The system, described by the tight-binding model with nonreciprocal hopping, is found to host two pairs of in-gap edge modes in the gapped topological phase and is characterized by the non-Hermitian (NH) Chern number $C_{NH}=2$. The quantization of the non-Hermitian Chern number is shown to be protected by the generalized rotational symmetry ${\hat{H}}^{+}=\hat{U}\hat{H}{\hat{U}}^{+}$ of the system. Our finding paves the way towards novel non-Hermitian topological systems characterized by large values of topological invariants and hosting multiple in-gap edge states, which can be used for topologically resilient multiplexing.

8 pages, 3 figures

References in corpus (4)

• Topological Photonics
• Classification of topological insulators and superconductors in three spatial dimensions
• Topological Crystalline Insulators
• Topological non-Hermitian origin of surface Maxwell waves

Cited by in corpus (5)

• Edge State, Band Topology, and Time Boundary Effect in the Fine-Grained Categorization of Chern Insulators
• Extension of Noether's theorem in PT-symmetric systems and its experimental demonstration in an optical setup
• Probing Bulk Band Topology from Time Boundary Effect in Synthetic Dimension
• Discriminant indicator with generalized rotational symmetry
• Hybrid Higher-Order Skin Topological Modes in the Two-Dimensional Su-Schrieffer-Heeger Model with Nonreciprocal Hoppings