Josephson junctions based on ultraclean carbon nanotubes

TL;DR

This paper introduces a new fabrication technique for ultraclean carbon nanotube Josephson junctions, preserving nanotube quality and enabling high-performance quantum devices.

Contribution

The authors develop a novel fabrication method that maintains nanotube cleanliness, resulting in high-quality Josephson junctions suitable for quantum computing applications.

Findings

High-quality Josephson junctions achieved

Suitable for quantum device applications

Preserves nanotube integrity during fabrication

Abstract

We present a technique for integrating ultraclean carbon nanotubes into superconducting circuits, aiming to realize Josephson junctions based on one-dimensional elementary quantum conductors. This technique primarily involves depositing the nanotube in the final step, thus preserving it from the inherent contaminations of nanofabrication and maintaining contact solely with superconducting electrodes and a crystalline hBN substrate. Through transport measurements performed in both the normal and superconducting states, we demonstrate that our method yields high-quality junctions with Josephson energies suitable for quantum device applications, such as carbon nanotube-based superconducting qubits.