Effects of interdot hopping and Coulomb blockade on the thermoelectric properties of serially coupled quantum dots

TL;DR

This paper theoretically investigates how interdot hopping and Coulomb interactions influence the thermoelectric efficiency of serially coupled quantum dots, revealing non-monotonic behavior and potential for Carnot efficiency under certain conditions.

Contribution

It provides analytical expressions for thermoelectric properties of SCQD considering Coulomb interactions and demonstrates their impact on efficiency and ZT.

Findings

ZT is not monotonically increasing with interdot hopping

SCQD can reach Carnot efficiency as interdot hopping approaches zero

Coulomb interactions significantly affect thermoelectric performance

Abstract

We have theoretically studied the thermoelectric properties of serially coupled quantum dots (SCQD) embedded in an insulator matrix connected to metallic electrodes. In the framework of Keldysh Green's function technique, the Landauer formula of transmission factor is obtained by using the equation of motion method. Based on such analytical expressions of charge and heat currents, we calculate the electrical conductance, Seebeck coefficient, electron thermal conductance and figure of merit (ZT) of SCQD in the linear response regime. The effects of electron Coulomb interactions on the reduction and enhancement of ZT are analyzed. We demonstrate that ZT is not a monotonic increasing function of interdot electron hopping strength ($t_c$). We also show that in the absence of phonon thermal conductance, SCQD can reach the Carnot efficiency as $t_c$ approaches zero.