Electron Transport and Hot Phonons in Carbon Nanotubes

TL;DR

This paper investigates how phonon occupation affects high-field electron transport in metallic carbon nanotubes, providing an analytic formula validated by first principles calculations and experimental data, revealing non-equilibrium phonon heating effects.

Contribution

It introduces a simple analytic formula for electron transport scattering length in nanotubes and demonstrates non-equilibrium optical phonon heating during electron transport.

Findings

Phonon occupation limits high-field ballistic transport.

Validated analytic formula matches first principles calculations.

Experimental data indicates non-equilibrium optical phonon heating.

Abstract

We demonstrate the key role of phonon occupation in limiting the high-field ballistic transport in metallic carbon nanotubes. In particular, we provide a simple analytic formula for the electron transport scattering length, that we validate by accurate first principles calculations on (6,6) and (11,11) nanotubes. The comparison of our results with the scattering lengths fitted from experimental I-V curves indicates the presence of a non-equilibrium optical phonon heating induced by electron transport. We predict an effective temperature for optical phonons of thousands Kelvin.