Tunable reciprocal and nonreciprocal contributions to 1D Coulomb Drag

TL;DR

This paper investigates both reciprocal and nonreciprocal Coulomb drag effects in coupled quantum wires, demonstrating their simultaneous presence and tunability, which advances understanding of low-dimensional electron interactions and potential energy harvesting applications.

Contribution

It provides the first experimental observation of tunable reciprocal and nonreciprocal Coulomb drag contributions in a single device with coupled quantum wires.

Findings

Both contributions are observed simultaneously.

The relative magnitudes are tunable by temperature and gate voltage.

The results suggest new avenues for studying Luttinger liquids and energy harvesting devices.

Abstract

Coulomb drag is a powerful tool to study interactions in coupled low-dimensional systems. Historically, Coulomb drag has been attributed to a frictional force arising from momentum transfer whose direction is dictated by the current flow. In the absence of electron-electron correlations, treating the Coulomb drag circuit as a rectifier of noise fluctuations yields similar conclusions about the reciprocal nature of Coulomb drag. In contrast, recent findings in one-dimensional systems have identified a nonreciprocal contribution to Coulomb drag that is independent of the current flow direction. In this work, we present Coulomb drag measurements between vertically coupled GaAs/AlGaAs quantum wires separated vertically by a hard barrier only 15 nm wide, where both reciprocal and nonreciprocal contributions to the drag signal are observed simultaneously, and whose relative magnitudes are temperature and gate tunable. Our study opens up the possibility of studying the physical mechanisms behind the onset of both Coulomb drag contributions simultaneously in a single device, ultimately leading to a better understanding of Luttinger liquids in multi-channel wires and paving the way for the creation of energy harvesting devices.