Electronic transport through a contact of a correlated quantum wire with leads of higher dimension

TL;DR

This paper theoretically investigates how non-smooth contacts between a quantum wire and higher-dimensional leads suppress electronic conduction below a threshold voltage, revealing a threshold-dependent current oscillation phenomenon influenced by electron interactions.

Contribution

It introduces a model showing the impact of contact smoothness on transport, highlighting a threshold voltage and oscillations due to electron interactions and Friedel oscillations.

Findings

Strong conduction suppression below threshold voltage V_T

Coherent current oscillations at frequency proportional to current

Effect is diminished at high temperatures or short channel lengths

Abstract

We study theoretically electronic transport through a contact of a quantum wire with 2D or 3D leads and find that if the contact is not smooth and adiabatic then the conduction is strongly suppressed below a threshold voltage $V_T$, while above $V_T$ the dc current $\bar I$ is accompanied by coherent oscillations of frequency $f=\bar I / e$. The effect is related to interelectronic repulsion and interaction of dc current with the Friedel oscillations near a sharp contact. In short conducting channels of length $L < L_0 \simeq \hbar v_F/eV_T$ and at high temperatures $T > T_0 \simeq eV_T/k_B$ the effect is destroyed by fluctuations.