High-temperature excess current and quantum suppression of electronic backscattering in a 1-D system

TL;DR

This paper investigates how quantum effects suppress electronic backscattering in a one-dimensional conductor, leading to a temperature- and bias-independent excess current at high bias voltages, with implications for measuring molecular properties.

Contribution

It demonstrates that quantum delocalization and Pauli exclusion cause a genuine excess current in 1D conductors, and shows how to measure target mass and vibration frequency from conductance data.

Findings

Quantum oscillations lead to excess current at high bias.

Backscattering suppression is due to quantum delocalization and Pauli exclusion.

Experimental observability in carbon nanotube systems.

Abstract

We consider the electronic current through a one-dimensional conductor in the ballistic transport regime and show that the quantum oscillations of a weakly pinned single scattering target results in a temperature- and bias-voltage independent excess current at large bias voltages. This is a genuine effect on transport that derives from an exponential reduction of electronic backscattering in the elastic channel due to quantum delocalization of the scatterer and from suppression of low-energy electron backscattering in the inelastic channels caused by the Pauli exclusion principle. We show that both the mass of the target and the frequency of its quantum vibrations can be measured by studying the differential conductance and the excess current. We apply our analysis to the particular case of a weakly pinned C60 molecule encapsulated by a single-wall carbon nanotube and find that the discussed phenomena are experimentally observable.