Joule heating and thermoelectric properties in short single-walled carbon nanotubes: electron-phonon interaction effect

TL;DR

This paper investigates how electron-phonon interactions influence Joule heating and thermoelectric properties in single-walled carbon nanotubes, revealing effects of chemical potential, temperature, and tube type on heat generation and conductance.

Contribution

It provides a theoretical analysis of EPI effects on Joule heating and thermoelectric properties in metallic and semiconducting nanotubes using nonequilibrium Green's functions.

Findings

Joule heat in metallic nanotubes aligns with experimental breakdown voltages.

Joule heat increases with chemical potential, less affected by temperature.

Electron-phonon interactions significantly impact conductance at high temperature or chemical potential.

Abstract

The electron-phonon interaction (EPI) effect in single-walled carbon nanotube is investigated by the nonequilibrium Green's function approach within the Born approximation. Special attention is paid to the EPI induced Joule heating phenomenon and the thermoelectric properties in both metallic armchair (10, 10) tube and semiconductor zigzag (10, 0) tube. For Joule heat in the metallic (10, 10) tube, the theoretical results for the breakdown bias voltage is quite comparable with the experimental value. It is found that the Joule heat can be greatly enhanced by increasing the chemical potential, while the role of the temperature is not so important for Joule heat. In zigzag (10, 0) tube, the Joule heat is smaller than the armchair tube, resulting from nonzero band gap in the electron band structure. For the electronic conductance $G_{e}$ and electron thermal conductance $\sigma_{el}$, the EPI has important effect at higher temperature or higher chemical potential. Compared with ballistic transport, there is an opposite tendency for $G_{e}$ to decrease with increasing temperature after EPI is considered. This is due to the dominant effect of the electron phonon scattering mechanism in the electron transport in this situation. There is an interesting `electron-drag' phenomenon for the phonon thermal conductance in case of low temperature and high chemical potential, where phonons are dragged by electrons from low temperature region into high temperature region through EPI effect.