Thermoelectric effect in molecular electronics

TL;DR

This paper theoretically estimates the thermoelectric effects in a molecular junction, showing the voltage's robustness and potential to reveal the Fermi energy position, which is crucial for understanding molecular conduction types.

Contribution

It provides a theoretical framework for analyzing thermoelectric effects in molecular electronics, highlighting the voltage's insensitivity to contact details and its usefulness in determining Fermi energy.

Findings

Thermoelectric voltage is easy to analyze and measurable.

Voltage is insensitive to contact coupling details.

Thermoelectric measurements can reveal the Fermi energy location.

Abstract

We provide a theoretical estimate of the thermoelectric current and voltage over a Phenyldithiol molecule. We also show that the thermoelectric voltage is (1) easy to analyze, (2) insensitive to the detailed coupling to the contacts, (3) large enough to be measured and (4) give valuable information, which is not readily accessible through other experiments, on the location of the Fermi energy relative to the molecular levels. The location of the Fermi-energy is poorly understood and controversial even though it is a central factor in determining the nature of conduction (n- or p-type). We also note that the thermoelectric voltage measured over Guanine molecules with an STM by Poler et al., indicate conduction through the HOMO level, i.e., p-type conduction.