Quantum transport in a one-dimensional quasicrystal with mobility edges

TL;DR

This paper investigates quantum transport in a 1D quasiperiodic lattice with mobility edges, revealing how localization transitions affect edge mode pumping, transfer phenomena, and nonreciprocal transport, with implications for quantum device engineering.

Contribution

It introduces the role of mobility edges in quantum transport within 1D quasiperiodic systems, highlighting their impact on adiabatic pumping and nonreciprocal effects, which were not previously explored.

Findings

Adiabatic pumping success depends on localization-delocalization transitions.

Mobility edges cause opposite outcomes in pumping compared to the Aubry-André model.

A parametric regime exhibits nonreciprocal, unidirectional transport.

Abstract

Quantum transport in a one-dimensional (1D) quasiperiodic lattice with mobility edges is explored. We first investigate the adiabatic pumping between left and right edge modes by resorting to two edge-bulk-edge channels and demonstrate that the success or failure of the adiabatic pumping depends on whether the corresponding bulk subchannel undergoes a localization-delocalization transition. Compared with the paradigmatic Aubry-Andr\'e (AA) model, the introduction of mobility edges triggers an opposite outcome for successful pumping in the two channels, showing a discrepancy of critical condition, and facilitates the robustness of the adiabatic pumping against quasidisorder. We also consider the transfer between excitations at both boundaries of the lattice and an anomalous phenomenon characterized by the enhanced quasidisorder contributing to the excitation transfer is found. Furthermore, there exists a parametric regime where a nonreciprocal effect emerges in the presence of mobility edges, which leads to a unidirectional transport for the excitation transfer and enables potential applications in the engineering of quantum diodes.