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

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 the zigzag (10, 0) tube, the Joule heat is smaller than the armchair tube, resulting from nonzero bandgap in the electron band structure. For the electronic conductance Ge and electron thermal conductance σel, the EPI has important effect at higher temperature or higher chemical potential. Compared with ballistic transport, there is an opposite tendency for Ge 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.