Contact resistance of quantum tubes

TL;DR

This paper investigates the conductance and contact resistance of quantum tubes, such as carbon nanotubes, when connected to metallic contacts, highlighting how radial confinement influences electron transmission.

Contribution

It provides a calculation of transmission coefficients for quantum tubes with different radial confinements and relates these to realistic carbon nanotube-metal contact scenarios.

Findings

Transmission can approach unity with realistic confinement.

Contact resistance near h/2e^2 per band at Fermi level.

Results applicable to armchair carbon nanotubes with Al and Au contacts.

Abstract

We consider the conductance of a quantum tube connected to a metallic contact. The number of angular momentum states that the tube can support depends on the strength of the radial confinement. We calculate the transmission coefficients which yield the conductance via the Landauer formula. We relate our results to armchair carbon nanotubes embedded in a metal. For Al and Au contacts and tubes with a realistic radial confinement we find that the transmission can be close to unity corresponding to a contact resistance close to h/2e^2 per band at the Fermi level in the carbon nanotube.