Mechanism for large thermoelectric power in molecular quantum dots described by the negative-UAnderson model

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 $\ensuremath{\mu}$V/K over a wide range of gate voltages.