Thermoelectric phenomena in a quantum dot asymmetrically coupled to external leads

TL;DR

This paper investigates thermoelectric effects in a strongly correlated quantum dot system in the Kondo regime, focusing on how asymmetry in lead couplings influences electrical, thermal conductance, and thermopower.

Contribution

It provides a detailed analysis of linear and nonlinear thermoelectric properties considering coupling asymmetry, highlighting changes in conductance and thermopower in different regimes.

Findings

Thermopower remains unchanged in the linear regime despite coupling asymmetry.

Nonlinear regime shows Kondo resonance at non-zero bias affecting thermoelectric properties.

Asymmetry influences thermopower dependence and the development of the Kondo resonance.

Abstract

We study thermoelectric phenomena in a system consisting of strongly correlated quantum dot coupled to external leads in the Kondo regime. We calculate linear and nonlinear electrical and thermal conductance and thermopower of the quantum dot and discuss the role of asymmetry in the couplings to external electrodes. In the linear regime electrical and thermal conductances are modified, while thermopower remains unchanged. In the nonlinear regime the Kondo resonance in differential conductance develops at non-zero source-drain voltage, which has important consequences on thermoelectric properties of the system and the thermopower starts to depend on the asymmetry. We also discuss Wiedemann-Franz relation, thermoelectric figure of merit and validity of the Mott formula for thermopower.