Orbital Kondo effect in a parallel double quantum dot

TL;DR

This paper presents a theoretical model for the orbital Kondo effect in a parallel double quantum dot, successfully reproducing experimental results and exploring the effects of interdot tunneling and pseudospin dynamics.

Contribution

The study provides a comprehensive theoretical analysis of the orbital Kondo effect in DQDs, including the impact of interdot tunneling and pseudospin-resolved transport, extending previous experimental findings.

Findings

Reproduces experimental conductance peaks in pseudospin-resolved Kondo effect.

Identifies up to four Kondo peaks with non-equal lead voltages.

Discovers new Kondo peaks and dips when interdot tunneling is introduced.

Abstract

We construct a theoretical model to study the orbital Kondo effect in a parallel double quantum dot (DQD). Recently, pseudospin-resolved transport spectroscopy of the orbital Kondo effect in a DQD has been experimentally reported. The experiment revealed that when interdot tunneling is ignored, there exist two and one Kondo peaks in the conductance-bias curve for the pseudospin-non-resolved and pseudospin-resolved cases, respectively. Our theoretical studies reproduce this experimental result. We also investigate the situation of all lead voltages being non-equal (the complete pseudospin-resolved case), and find that there are four Kondo peaks at most in the curve of the conductance versus the pseudospin splitting energy. When the interdot tunneling is introduced, some new Kondo peaks and dips can emerge. Besides, the pseudospin transport and the pseudospin flipping current are also studied in the DQD system. Since the pseudospin transport is much easier to be controlled and measured than the real spin transport, it can be used to study the physical phenomenon related to the spin transport.