Efficiency and power of a thermoelectric quantum dot device

TL;DR

This paper analyzes the thermoelectric performance of a quantum dot device under linear and nonequilibrium conditions, focusing on how interactions influence efficiency and power output.

Contribution

It provides a detailed study of interaction effects on thermoelectric efficiency and power in a quantum dot system, including both linear response and nonequilibrium regimes.

Findings

Interactions reduce maximum efficiency in linear response.

Resonance line shape renormalization explains thermoelectric property changes.

Certain parameters allow increased efficiency at fixed power in nonequilibrium.

Abstract

We study linear response and nonequilibrium steady-state thermoelectric transport through a single-level quantum dot tunnel coupled to two reservoirs held at different temperatures as well as chemical potentials. A fermion occupying the dot interacts with those in the reservoirs by a short-ranged two-particle interaction. For parameters for which particles flow against a bias voltage from the hot to the cold reservoir this setup acts as an energy-conversion device with which electrical energy is gained out of waste heat. We investigate how correlations affect its efficiency and output power. In linear response the changes in the thermoelectric properties can be traced back to the interaction induced renormalization of the resonance line shape. In particular, small to intermediate repulsive interactions reduce the maximum efficiency. In nonequilibrium the situation is more complex and we identify a parameter regime in which for a fixed lower bound of the output power the efficiency increases.