Manipulability of the Kondo effect in a T-shaped triple-quantum-dot structure

TL;DR

This paper explores the complex Kondo physics in a T-shaped triple-quantum-dot system, revealing multiple transition processes and conductance behaviors influenced by electron-hole symmetry and interdot couplings.

Contribution

It provides a theoretical analysis of the Kondo effect in a triple-quantum-dot structure using numerical renormalization group methods, highlighting new transition phenomena and conductance dependencies.

Findings

Identification of three-stage Kondo effect at electron-hole symmetry

Observation of Kondo resonance in conductance spectrum under symmetry breaking

Dependence of Kondo phenomena on Coulomb interaction and interdot couplings

Abstract

We theoretically investigate the Kondo effect of a T-shaped triple-quantum-dot structure, by means of the numerical renormalization group method. It is found that at the point of electron-hole symmetry, the system's entropy has opportunities to exhibit three kinds of transition processes for different interdot couplings, with the decrease of temperature. This leads to the different pictures of the Kondo physics, including the three-stage Kondo effect. Next when the electron-hole symmetry is broken or the structural parameters are changed, the Kondo resonance can also be observed in the conductance spectrum. However, it shows alternative dependence on the relevant quantities, i.e., the Coulomb interaction and interdot couplings. All these phenomena exhibit the abundant and interesting Kondo physics in this system. We believe that this work can be helpful for further understanding the Kondo effect in the triple-quantum-dot structures.