Multiple mobility rings in non-Hermitian Su-Schrieffer-Heeger chain with quasiperiodic potentials

TL;DR

This paper explores how non-Hermitian quasi-periodic potentials induce multiple mobility rings in the SSH chain, revealing complex localization-delocalization transitions influenced by system parameters and mosaic modulation.

Contribution

It uncovers the existence of multiple mobility rings in non-Hermitian SSH chains with quasi-periodic potentials, highlighting new localization phenomena due to mosaic modulation.

Findings

Multiple mobility rings appear with increased mosaic modulation periods.

Localization-delocalization transition can be tuned by hopping strengths.

Distinct spectral behaviors observed under Hermitian and non-Hermitian conditions.

Abstract

The localization property of a non-Hermitian Su-Schrieffer-Heeger (SSH) chain with quasi-periodic on-site potential is investigated. In contrast to the preceding investigations, the quantum phase transition between localized state and extended one is achieved by adjusting the strength of intracellular or intercellular hopping. The energy spectra and eigenstate distributions of the system's Hamiltonian near the boundary of the phase transition exhibit different behaviors when the Hermiticity, non-Hermiticity and mosaic modulation of the quasi-periodic potential are considered, respectively. The existence of the mobility ring is revealed in the non-Hermitian SSH chain by studying of the critical behaviors near the boundary. More interestingly, the multiple mobility rings emerge when the period number of the mosaic modulation is increased. The result is helpful for the investigation of the localization-delocalization transition in the SSH-type system under the combined action of the non-Hermiticity and quasi-periodicity.