Zero-field Kondo splitting and quantum-critical transition in double quantum dots

TL;DR

This paper investigates how double quantum dots can be used to study many-body correlations, showing that Kondo resonance splitting occurs but the singlet ground state remains stable, and exploring quantum criticality.

Contribution

It demonstrates how a double quantum dot system can be tuned to explore Kondo physics and quantum critical points using numerical renormalization-group methods.

Findings

Kondo resonance splits due to band filtering

Singlet ground state remains robust

Quantum critical point accessible by tuning the system

Abstract

Double quantum dots offer unique possibilities for the study of many-body correlations. A system containing one Kondo dot and one effectively noninteracting dot maps onto a single-impurity Anderson model with a structured (nonconstant) density of states. Numerical renormalization-group calculations show that while band filtering through the resonant dot splits the Kondo resonance, the singlet ground state is robust. The system can also be continuously tuned to create a pseudogapped density of states and access a quantum critical point separating Kondo and non-Kondo phases.