Critical and excess current through an open quantum dot: Temperature and magnetic field dependence

TL;DR

This paper investigates how temperature and magnetic fields affect the critical and excess currents in a carbon nanotube Josephson quantum dot junction, providing experimental data and theoretical insights.

Contribution

It offers the first detailed measurements of critical and excess currents in an open quantum dot regime with a controlled fabrication process.

Findings

Good qualitative agreement with theoretical models

Method to extract quantum dot parameters from bias spectroscopy

Demonstrates temperature and magnetic field effects on supercurrent

Abstract

We present measurements of temperature and magnetic field dependence of the critical current and excess current in a carbon nanotube Josephson quantum dot junction. The junction is fabricated in a controlled environment which allows for extraction of the full critical current. The measurements are performed in the open quantum dot regime, and fitted to theory with good qualitative agreement. We also show how to extract level spacing, level broadening, and charging energy of an open quantum dot from a bias spectroscopy plot.