Thermopower of few-electron quantum dots with Kondo correlations

TL;DR

This paper investigates the thermopower behavior of few-electron quantum dots with Kondo correlations using a hierarchical equations of motion approach, revealing unconventional sign reversal due to multi-level effects and electron correlations.

Contribution

It introduces a detailed analysis of thermopower in multi-level quantum dots with Kondo effects, highlighting the role of inter-level spacing and correlations, which is a novel insight.

Findings

Unconventional sign reversal of thermopower predicted.

Multi-level effects significantly influence thermoelectric behavior.

Relations between thermopower and electron correlations elucidated.

Abstract

The thermopower of few-electron quantum dots with Kondo correlations is investigated via a hierarchial equations of motion approach. The thermopower is determined by the line shape of spectral function within a narrow energy window defined by temperature. Based on calculations and analyses on single-level and two-level Anderson impurity models, the underlying relations between thermopower and various types of electron correlations are elaborated. In particular, an unconventional sign reversal behavior is predicted for quantum dots with a suitable inter-level spacing. The new feature highlights the significance of multi-level effects and their interplay with Kondo correlations. Our finding and understanding may lead to novel thermoelectric applications of quantum dots.