Evaluation of the thermoelectric properties of a nanoscale device in the presence of an external electric field: Tight binding model

In this paper, we present a tight-binding model for investigating the thermoelectric properties of a molecular scale junction under an external electric field (EF). Such junction is made of a chain of benzene rings (oligophenylene) connected to similar metallic electrodes. Using the Landauer formalism within the framework of Green's function method, electrical transport properties, including the Seebeck coefficient (S), the electrical conductivity (G(e)), the thermal conductivity (K), and the figure of merit (ZT), are numerically calculated. It is shown that all thermoelectric characteristics are depended on the external EF strength and change the thermoelectric performance in the organic molecule. As a result, at room temperature T=300 K and zero EF, the maximum value of ZT is about 0.8, reaching almost 1.2 when EF=0.4 V/angstrom.

Automated summary

This paper presents a tight-binding model for investigating the thermoelectric properties of a molecular scale junction under an external electric field. The numerical calculations reveal that the electrical and thermal transport properties of the junction are dependent on the strength of the external electric field.