Effects of Disorder and Momentum Relaxation on the Intertube Transport of Incommensurate Carbon Nanotube Ropes and Multiwall Nanotubes

TL;DR

This paper investigates how disorder and momentum relaxation influence electrical transport between incommensurate carbon nanotubes and shells in multiwall nanotubes, revealing that disorder can significantly enhance conductance.

Contribution

The study provides a theoretical analysis of intertube transport considering disorder effects, showing how disorder enhances conductance in incommensurate nanotube systems.

Findings

Disorder dramatically increases intertube conductance.

Momentum conservation suppresses transport in clean nanotubes.

Experimental data aligns with short-range correlated disorder models.

Abstract

We study theoretically the electrical transport between aligned carbon nanotubes in nanotube ropes, and between shells in multiwall carbon nanotubes. We focus on transport between two metallic nanotubes (or shells) of different chiralities with mismatched Fermi momenta and incommensurate periodicities. We perform numerical calculations of the transport properties of such systems within a tight-binding formalism. For clean (disorder-free) nanotubes the intertube transport is strongly suppressed as a result of momentum conservation. For clean nanotubes, the intertube transport is typically dominated by the loss of momentum conservation at the contacts. We discuss in detail the effects of disorder, which also breaks momentum conservation, and calculate the effects of localised scatterers of various types. We show that physically relevant disorder potentials lead to very dramatic enhancements of the intertube conductance. We show that recent experimental measurements of the intershell transport in multiwall nanotubes are consistent with our theoretical results for a model of short-ranged correlated disorder.