Time delay in a disordered topological system

TL;DR

This paper investigates how disorder affects the time delay of topologically protected edge states in a quasi-1D Haldane model, revealing insights into localized modes and disorder strength effects.

Contribution

It introduces a generalized eigenchannel time delay concept for topological systems and proposes a method to extract localized mode parameters from time delay measurements.

Findings

Time delay fluctuations increase with disorder strength.

Eigenchannel time delay relates to the density of states.

Method to determine localized mode frequency and linewidth.

Abstract

The discovery of topological insulators has opened new prospects for robust signal transport for electronic, phononic, and photonic devices. Though transport of topological protected edge states is robust to disorder, large fluctuations and lengthened average delay time are observed. Here, we consider a quasi-1d system following the Haldane model and generalize the idea of eigenchannel time delay to the topological system. Eigenchannel time delay indicates the excited density of states for the configuration and relates to the intensity integral inside the system. Taking advantage of this property, we point out a practical way to extract the central frequency and linewidth of localized modes excited in the topological system. This work links the fluctuation of time delay to the strength of disorder and discusses the scaling of time delay.