Thermopower for a molecule with vibrational degrees of freedom

TL;DR

This paper introduces an analytical model for thermopower in molecular junctions considering vibrational modes, revealing unique behaviors and providing a benchmark for future studies.

Contribution

It presents a simple analytical model for thermopower in vibrationally active molecules, offering explicit formulas and insights into thermal transport in nanodevices.

Findings

Analytical expressions for thermopower and Seebeck coefficient derived.

Identification of a regime with peculiar thermopower behavior.

Model serves as a benchmark for complex computational methods.

Abstract

We propose a simple model to study resonant tunneling through an organic molecule between to conducting leads, taking into account the vibrational modes of the molecule. We solve the model approximately analytically in the weak coupling limit and give explicit expressions for the thermopower and Seebeck coefficient. The behavior of these two quantities is studied as function of model parameters and temperature. For a certain regime of parameters a rather peculiar variation of the thermopower and Seebeck coefficient is observed. Although the model is very simple, we expect it to give some nontrivial insight into thermal transport properties through nan-devices. Furthermore, because we can provide an analytical solution, it may eventually serve as benchmark for more advanced analytical or computational methods.