Dependence of transport through carbon nanotubes on local Coulomb potential

TL;DR

This study investigates how local Coulomb potentials affect electron transport in carbon nanotubes, revealing conductance peak shifts in semiconducting types and degeneracy preservation in metallic types at helium temperatures.

Contribution

It demonstrates the impact of a mobile AFM tip as a local gate on transport properties, providing insights into quantum behavior in nanotubes.

Findings

Conductance peaks shift with tip position in semiconducting nanotubes.

Fourfold degeneracy remains in metallic nanotubes despite local Coulomb potential.

Transport behavior aligns with a particle in a box quantum model.

Abstract

In this paper, we present the results of helium temperature transport measurements through carbon nanotubes using an AFM conductive tip as a mobile gate. In semiconducting nanotubes we observe shifting of the conductance peaks with changing of the AFM tip position. This result can be explained with a particle in the box quantum model. In high quality metallic nanotubes we observe that the local Coulomb potential does not destroy the fourfold degeneracy of the energy levels.