High field electro-thermal transport in metallic carbon nanotubes

TL;DR

This paper presents a semi-classical model for high-field electro-thermal transport in metallic carbon nanotubes, explaining electrical behavior and self-heating effects with a focus on charge-heat interactions.

Contribution

It introduces a self-consistent Boltzmann and heat equation approach that accounts for non-equilibrium phonons and local thermalization in metallic CNTs.

Findings

Model accurately reproduces room temperature electrical characteristics.

Negative differential resistance is due to inhomogeneous field profiles from self-heating.

Charge-heat transport insights applicable to one-dimensional nanostructures.

Abstract

We describe the electro-thermal transport in metallic carbon nanotubes (m-CNTs) by a semi-classical approach that takes into account the high-field dynamical interdependence between charge carrier and phonon populations. Our model is based on the self-consistent solution of the Boltzmann transport equation and the heat equation mediated by a phonon rate equation that accounts for the onset of non-equilibrium (optical) phonons in the high-field regime. Given the metallic nature of the nanostructures, a key ingredient of the model is the assumption of local thermalization of charge carriers. Our theory remarkably reproduces the room temperature electrical characteristics of m-CNTs on substrate and free standing (suspended), shedding light on charge-heat transport in these one dimensional nanostructures. In particular, the negative differential resistance observed in suspended m-CNTs under electric stress is attributed to inhomogeneous field profile induced by self-heating rather than the presence of hot phonons.