Interplay between Josephson effect and magnetic interactions in double quantum dots

TL;DR

This paper studies how magnetic interactions and the Josephson effect influence transport in double quantum dots with superconducting leads, revealing complex magnetic behavior and potential control of magnetic states via Josephson current.

Contribution

It introduces an analysis of magnetic and transport properties in double quantum dots with superconducting contacts, highlighting the interplay between Kondo effect, inter-dot coupling, and Josephson current.

Findings

Identification of phase transitions to a $$ state.

Demonstration of magnetic configuration control via Josephson current.

Revelation of rich magnetic behavior due to competing interactions.

Abstract

We analyze the magnetic and transport properties of a double quantum dot coupled to superconducting leads. In addition to the possible phase transition to a $\pi$ state, already present in the single dot case, this system exhibits a richer magnetic behavior due to the competition between Kondo and inter-dot antiferromagnetic coupling. We obtain results for the Josephson current which may help to understand recent experiments on superconductor-metallofullerene dimer junctions. We show that in such a system the Josephson effect can be used to control its magnetic configuration.