Stable topological edge states in a non-Hermitian four-band model

Abstract

We introduce a one-dimensional non-Hermitian four-band tight-binding lattice system. We find stable topological edge states protected by particle-hole and parity-time symmetries. We show that a topological phase appears in the system. We discuss that the system can also be used as a topological laser if the gain and loss positions in a unit cell are judiciously arranged.