Quasi-1D Coulomb drag in the nonlinear regime

TL;DR

This study measures Coulomb drag between coupled quantum wires in the nonlinear regime at ultra-low temperatures, revealing oscillatory behavior and non-Fermi-liquid characteristics consistent with Tomonaga-Luttinger liquid theory.

Contribution

It provides the first experimental evidence of nonlinear Coulomb drag in quasi-1D systems, extending theoretical predictions beyond the linear response regime.

Findings

Nonlinear dependence of drag voltage on drive current

Oscillatory contributions in Coulomb drag observed

Nonmonotonic temperature dependence of I-V characteristics

Abstract

One-dimensional Coulomb drag has been an essential tool to probe the physics of interacting Tomonaga-Luttinger liquids. To date, most experimental work has focused on the linear regime while the predictions for Luttinger liquids beyond the linear response theory remain largely untested. In this letter, we report measurements of momentum transfer induced Coulomb drag between vertically-coupled quasi-one-dimensional quantum wires in the nonlinear regime. Measurements were performed at ultra-low temperatures between wires only 15 nm apart. Our results reveal a nonlinear dependence of the drag voltage as a function of the drive current superimposed with an oscillatory contribution, in agreement with theoretical predictions for Coulomb drag between Tomonaga-Luttinger liquids. Additionally, the observed current-voltage ($I$-$V$) characteristics exhibit a nonmonotonic temperature dependence, further corroborating the presence of non-Fermi-liquid behavior in our system. These findings are observed both in the single and in the multiple subband regimes and in the presence of disorder, extending the onset of this behavior beyond the clean single channel Tomonaga-Luttinger regime where the predictions were originally formulated.