Conductance in multiwall carbon nanotubes and semiconductor nanowires : evidence of a universal tunneling barrier

TL;DR

This study reveals a universal tunneling barrier in multiwall carbon nanotubes and semiconductor nanowires, characterized by a consistent conductance scaling law and weak localization, explained through Coulomb blockade theory.

Contribution

It demonstrates a universal conductance behavior and tunneling barrier in different nanostructures, unifying their electronic transport properties under a common framework.

Findings

Universal conductance scaling law with a single coefficient  in all samples

Weak localization observed in magnetoconductance measurements

Consistent tunnel resistance and Thouless energy across samples

Abstract

Electronic transport in multiwall carbon nanotubes and semiconductor nanowires was compared. In both cases, the non ohmic behavior of the conductance, the so-called zero bias anomaly, shows a temperature dependence that scales with the voltage dependence. This robust scaling law describes the conductance $G(V,T)$ by a single coefficient $\alpha$. A universal behavior as a function of $\alpha$ is found for all samples. Magnetoconductance measurements furthermore show that the conduction regime is weak localization. The observed behavior can be understood in terms of the coulomb blockade theory, providing that a unique tunnel resistance on the order of 2000 $\Omega$ and a Thouless energy of about 40 meV exists for all samples.