Mechanism for large thermoelectric power in negative-U molecular quantum dots

TL;DR

This paper demonstrates that the charge Kondo effect in negative-U molecular quantum dots significantly enhances thermoelectric power, achieving high Seebeck coefficients through correlation-induced spectral asymmetry.

Contribution

It introduces a novel mechanism linking the charge Kondo effect to enhanced thermoelectric performance in negative-U quantum dots, supported by numerical renormalization group analysis.

Findings

Seebeck coefficients exceeding 50 μV/K over wide gate voltage ranges.

Charge Kondo effect causes spectral asymmetry near the Fermi level.

Enhanced thermopower due to correlation effects in negative-U systems.

Abstract

We investigate with the aid of numerical renormalization group techniques the thermoelectric properties of a molecular quantum dot described by the negative-U Anderson model. We show that the charge Kondo effect provides a mechanism for enhanced thermoelectric power via a correlation induced asymmetry in the spectral function close to the Fermi level. We show that this effect results in a dramatic enhancement of the Kondo induced peak in the thermopower of negative-U systems with Seebeck coefficients exceeding 50$\mu V/K$ over a wide range of gate voltages.