Non-Hermitian total-loss high-order topological insulator based on 1D Su-Schrieffer-Heeger (SSH)

TL;DR

This paper introduces a novel two-dimensional non-Hermitian high-order topological insulator based on a 1D SSH chain, where total loss induces nontrivial topology and supports real-energy edge states, advancing topological physics in lossy systems.

Contribution

It reveals a new way to realize high-order topological insulators using total loss in a 1D SSH chain, expanding the understanding of non-Hermitian topological phases.

Findings

Total loss induces nontrivial topology in 2D systems.

Existence of real-energy edge states in pseudo-PT symmetric domain walls.

Band gap with corner and edge states characterized by gapped Wannier bands.

Abstract

Non-Hermiticity alters topology with the presence of non-Hermitian factors in topological systems. Most existing non-Hermitian topological systems derive their topological phases from Hermitian components, that is, the gain and loss of the system are considered simultaneously. In this work, we reveal two-dimensional non-Hermitian high-order topological insulator based on one-dimensional SSH chain, the nontrivial topology of which induced by total-loss. By introducing the loss of a specific configuration, we get a band gap with corner and edge states whose topology is characterized by the gapped wannier band. In addition, we demonstrate the existence of 'real-energy' edge states in pseudo-PT symmetric domain wall system. These results can be easily implemented in experiments, and promote the research of topological transmission of lossy systems in the real world.