Topology of a parity-time symmetric non-Hermitian rhombic lattice

We investigate the topological properties of a trimerized parity-time (PT) symmetric non-Hermitian rhombic lattice. Although the system is PT-symmetric, the topology is not inherited from the Hermitian lattice; in contrast, the topology can be altered by the non-Hermiticity and depends on the couplings between the sublattices. The bulk-boundary conespondence is valid and the Bloch bulk captures the band topology. Topological edge states present in the two band gaps and are predicted from the global Zak phase obtained through the Wilson loop approach. In addition, the anomalous edge states compactly localize within two diamond plaquettes at the boundaries when all bands are flat at the exceptional point of the lattice. Our findings reveal the topological properties of the PT-symmetric non-Hermitian rhombic lattice and shed light on the investigation of multi-band non-Hermitian topological phases.

Automated summary

We investigated the topological properties of a trimerized PT-symmetric non-Hermitian rhombic lattice. The system's topology is not inherited from the Hermitian lattice but is altered by non-Hermiticity and depends on the couplings between the sublattices. The presence of topological edge states in the two band gaps and their localization at the boundaries are predicted through the global Zak phase obtained from the Wilson loop approach.