Anomalous Josephson current through a spin-orbit coupled quantum dot

TL;DR

This paper investigates the conditions under which a mesoscopic quantum dot with spin-orbit coupling exhibits an anomalous Josephson current, revealing the roles of spin-orbit interaction, Zeeman field, and chirality.

Contribution

It provides analytical expressions and identifies the key conditions for the emergence of anomalous Josephson current in multi-level quantum dots.

Findings

Finite spin-orbit coupling is necessary.

A specific Zeeman field orientation is required.

The quantum dot must be a chiral conductor.

Abstract

For a general model of a mesoscopic multi-level quantum dot, we determine the necessary conditions for the existence of an anomalous Josephson current with spontaneously broken time-reversal symmetry. They correspond to a finite spin-orbit coupling, a suitably oriented Zeeman field, and the dot being a chiral conductor. We provide analytical expressions for the anomalous supercurrent covering a wide parameter regime.