Reentrant Localized Bulk and Localized-Extended Edge in Quasiperiodic Non-Hermitian Systems

TL;DR

This paper investigates the complex localization behaviors of bulk and edge states in a quasiperiodic non-Hermitian system, revealing multiple phase transitions and novel oscillatory phenomena, advancing understanding in topological physics.

Contribution

It introduces a systematic method to analyze localization in quasiperiodic non-Hermitian systems, uncovering multiple transitions and edge state behaviors linked to topological phases.

Findings

Bulk undergoes multiple localization transitions induced by quasidisorder and non-Hermiticity.

Edge states are broken and recovered with increasing disorder, synchronized with topological phase transitions.

Derivative of participation ratio shows discontinuity at localization transition.

Abstract

The localization is one of the active and fundamental research in topology physics. Based on a generalized Su-Schrieffer-Heeger model with the quasiperiodic non-Hermitian emerging at the off-diagonal location, we propose a novel systematic method to analyze the localization behaviors for the bulk and the edge, respectively. For the bulk, it can be found that it undergoes an extended-coexisting-localized-coexisting-localized transition induced by the quasidisorder and nonHermiticity. While for the edge state, it can be broken and recovered with the increase of the quasidisorder strength, and its localized transition is synchronous exactly with the topological phase transition. In addition, the inverse participation ratio of the edge state oscillates with an increase of the disorder strength. Finally, numerical results elucidate that the derivative of the normalized participation ratio exhibits an enormous discontinuity at the localized transition point. Here, our results not only demonstrate the diversity of localization properties of bulk and edge state, but also may provide an extension of the ordinary method for investigating the localization.