Thermopower, figure of merit, quantum dot, Kondo effect, orbital degrees of freedom

TL;DR

This paper investigates how the orbital Kondo effect influences thermopower and transport properties in a quantum dot system, revealing unique temperature-dependent behaviors modulated by gate voltage and magnetic field.

Contribution

It introduces a detailed analysis of thermopower in multiorbital quantum dots affected by the orbital Kondo effect using the noncrossing approximation.

Findings

Asymmetry in tunneling resonance affects thermopower behavior.

Thermopower exhibits characteristic temperature dependence under control parameters.

Comparison with spin Kondo effect highlights unique features of orbital Kondo effect.

Abstract

We study the thermopower and some related transport quantities due to the orbital Kondo effect in a single quantum dot system with a finite value of Coulomb repulsion by means of the noncrossing approximation applied to the multiorbital impurity Anderson model. It is elucidated how the asymmetry of the renormalized tunneling resonance due to the two-orbital Kondo effect causes characteristic behavior of the thermopower at finite temperatures under gate-voltage and magnetic-field control, which is compared with that of the ordinary spin Kondo effect.