Superconducting Transport in single and parallel double InAs Quantum Dot Josephson Junctions with Nb-based Superconducting Electrodes

TL;DR

This paper investigates superconducting transport in InAs quantum dot Josephson junctions with Nb-based electrodes, revealing enhanced supercurrent in double-dot configurations and highlighting the properties of Nb superconductors.

Contribution

It presents the first detailed measurements of conductance and supercurrent in single and double InAs quantum dot Josephson junctions with Nb electrodes, demonstrating split Cooper pair tunneling effects.

Findings

Large superconducting gap and high critical field observed.

Enhanced supercurrent when both dots are on resonance.

Evidence of split Cooper pair tunneling in double dots.

Abstract

We report conductance and supercurrent measurements for InAs single and parallel double quantum dot Josephson junctions contacted with Nb or NbTiN superconducting electrodes. Large superconducting gap energy, high critical field and large switching current are observed, all reflecting the features of Nb-based electrodes. For the parallel double dots we observe an enhanced supercurrent when both dots are on resonance, which may reflect split Cooper pair tunneling.