The effect of Coulomb interactions on nonlinear thermovoltage and thermocurrent in quantum dots

TL;DR

This paper theoretically examines how Coulomb interactions influence nonlinear thermovoltage and thermocurrent in quantum dots, revealing transitions from Coulomb blockade to Kondo regimes using advanced Green's functions methods.

Contribution

It introduces a nonequilibrium Green's functions approach beyond Hartree-Fock to analyze thermoelectric transport in quantum dots, capturing Coulomb blockade and Kondo effects.

Findings

Identification of thermovoltage zeros under thermal gradients

Transition from Coulomb blockade to Kondo regime in thermoelectric transport

Theoretical framework applicable to experimental observations

Abstract

In the present work, we theoretically study the nonlinear regime of charge transport through a quantum dot coupled to the source and drain reservoirs. The investigation is carried out using a nonequilibrium Green's functions formalism beyond the Hartree-Fock approximation. Employed approximations for the relevant Green's functions allow to trace a transition from Coulomb blockade regime to Kondo regime in the thermoelectric transport. Effects arising when electrons move in response to thermal gradient applied across the system are discussed, including experimentally observed thermovoltage zeros.