Phonon-assisted thermoelectric effects in a two-level molecule

TL;DR

This paper investigates how phonon interactions influence thermoelectric properties in a two-level molecular system, revealing significant effects on conductance, thermal behavior, and fundamental laws like Wiedemann-Franz.

Contribution

It provides a detailed analysis of phonon-assisted thermoelectric effects in a molecular system using Green function formalism, highlighting the impact of electron-phonon coupling.

Findings

Electrical conductance depends on electron and phonon temperatures.

Strong electron-phonon interaction suppresses thermal conductance peaks.

Wiedemann-Franz law is violated due to Coulomb interactions.

Abstract

Thermoelectric properties of a two-level molecule attached to the metallic electrodes are analyzed using the equation of motion technique within the Green function formalism. Results show that the electrical conductance is strongly dependent on the electron and phonon temperatures and the electron-phonon coupling strength. In addition, it is observed that the thermal conductance peaks in the electron-hole symmetry points are vanished in the presence of the strong electron-phonon interaction. It is also found that the figure of merit is strongly suppressed in the strong electron-phonon interaction. The violation of the Wiedemann-Franz law is also observed coming from the Coulomb interactions.