Intershell resistance in multiwall carbon nanotubes: A Coulomb drag study

TL;DR

This study calculates the intershell resistance in multiwall carbon nanotubes using Coulomb drag theory, revealing strong chirality-dependent effects and sign changes in resistance influenced by Fermi level and tube structure.

Contribution

It provides benchmark calculations of intershell resistance considering chirality effects and classifies metallic nanotubes based on their angular momentum properties.

Findings

Resistances vary greatly with chirality and Fermi level.

Resistance can change sign depending on tube chirality.

A dip or peak in resistance occurs at electron-hole symmetry points.

Abstract

We calculate the intershell resistance R_{21} in a multiwall carbon nanotube as a function of temperature T and Fermi level (e.g. a gate voltage), varying the chirality of the inner and outer tubes. This is done in a so-called Coulomb drag setup, where a current I_1 in one shell induces a voltage drop V_2 in another shell by the screened Coulomb interaction between the shells neglecting the intershell tunnelling. We provide benchmark results for R_{21}=V_2/I_1 within the Fermi liquid theory using Boltzmann equations. The band structure gives rise to strongly chirality dependent suppression effects for the Coulomb drag between different tubes due to selection rules combined with mismatching of wave vector and crystal angular momentum conservation near the Fermi level. This gives rise to orders of magnitude changes in R_{21} and even the sign of R_{21} can change depending on the chirality of the inner and outer tube and misalignment of inner and outer tube Fermi levels. However for any tube combination, we predict a dip (or peak) in R_{21} as a function of gate voltage, since R_{21} vanishes at the electron-hole symmetry point. As a byproduct, we classified all metallic tubes into either zigzag-like or armchair-like, which have two different non-zero crystal angular momenta m_a, m_b and only zero angular momentum, respectively.