Thermal efficiency of carbon nanotube quantum dots in the presence of electron-phonon interaction

Thermoelectric properties of a carbon nanotube quantum dot such as electrical conductance, thermal conductance, thermopower, and figure of merit are analyzed. Influence of electron-electron, spin-orbit, and electron-phonon (EPI) interactions on the thermoelectric properties of system is taken into account using the Green function formalism in the linear response regime. It is observed that the temperature difference between electron and phonon subsystems results in the fluctuation of the thermopower and enhancement of the figure of merit. It is also found that the figure of merit is reduced in high temperatures due to the bipolar effect induced by the EPI resulting in the reduction of electrical conductance and increase of thermal conductance.