Josephson current through interacting double quantum dots with spin-orbit coupling

TL;DR

This paper investigates how Rashba spin-orbit interaction influences the Josephson current in double quantum dots with Coulomb repulsion, revealing conditions for observing the -phase and effects of device parameters.

Contribution

It provides a comprehensive analysis of spin-orbit effects on Josephson current in double quantum dots, including temperature and magnetic field orientation impacts.

Findings

Spin-orbit interaction induces -phase at finite temperatures.

Device asymmetry and magnetic field orientation significantly affect the Josephson current.

Orthogonal spin-orbit component mimics Coulomb interaction effects, enabling -phase observation.

Abstract

We study the effect of Rashba spin-orbit interaction on the Josephson current through a double quantum dot in presence of Coulomb repulsion. In particular, we describe the characteristic effects on the magnetic-field induced singlet-triplet transition in the molecular regime. Exploring the whole parameter space, we analyze the effects of the device asymmetry, the orientation of the applied magnetic field with respect to the spin-orbit interaction, and finite temperatures. We find that at finite temperatures the orthogonal component of the spin-orbit interaction exhibits a similar effect as the Coulomb interaction inducing the occurrence of a {\pi}-phase at particle-hole symmetry. This provides a new route to the experimental observability of the {\pi}-phase in multi-level quantum dots.