The Two-impurity Anderson Model Revisited: Competition between Kondo Effect and Reservoir-mediated Superexchange in Double Quantum Dots

TL;DR

This paper investigates the competition between Kondo effect and a newly identified reservoir-mediated superexchange in double quantum dots, revealing experimental signatures of this novel interaction.

Contribution

It introduces a new conduction-band mediated superexchange mechanism in the two-impurity Anderson model, expanding understanding of interactions in double quantum dots.

Findings

Identification of a new superexchange interaction competing with Kondo physics.

Numerical results showing the impact of this interaction on transport properties.

Predictions of observable effects in double quantum dot experiments.

Abstract

We study a series-coupled double quantum dot in the Kondo regime modeled by the two-impurity Anderson model and find a new conduction-band mediated superexchange interaction that competes with Kondo physics in the strong Coulomb interaction limit. Our numerical renormalization group results, complemented with the higher-order Rayleigh-Schr\"odinger perturbation theory, show that the novel exchange mechanism leads to clear experimental consequences that can be checked in transport measurements through double quantum dots.