Transport characteristics of bulk and edge states in an off-diagonal Aubry--Andr\'e--Harper chain

TL;DR

This study explores how internal boundaries and quantum coherence affect transport in an off-diagonal Aubry--Andre9--Harper chain, revealing distinct behaviors of edge, bulk, and band-edge states.

Contribution

It demonstrates the influence of internal boundaries and coupling strength on transport signatures and the transition from tunneling to ballistic transport in the system.

Findings

Edge, in-band bulk, and band-edge bulk states have distinct transport signatures.

Bulk states near edges behave like edge states with weak size dependence.

Chain-electrode coupling controls resonance broadening and transport regime crossover.

Abstract

We investigate quantum transport in an off-diagonal Aubry--Andr\'e--Harper chain. The periodic hopping modulation generates effective internal boundaries that strongly influence the transmission characteristics. We show that edge, in-band bulk, and band-edge bulk states can be clearly distinguished through their transport signatures. In particular, bulk states near the band edges exhibit behavior similar to edge states, with weak dependence on system size, whereas in-band bulk states display pronounced size-dependent oscillations. We further demonstrate that the chain--electrode coupling strength controls the broadening of transmission resonances and drives a crossover from tunneling-dominated to nearly ballistic transport. In addition, dephasing introduces distinct sensitivity across different state classes, depending on their degree of spatial localization. These results highlight the key role of internal boundaries and quantum coherence in governing transport in modulated one-dimensional systems.