Josephson junctions based on ultraclean carbon nanotubes

We present a technique for integrating ultraclean carbon nanotubes into\nsuperconducting circuits, aiming to realize Josephson junctions based on\none-dimensional elementary quantum conductors. This technique primarily\ninvolves depositing the nanotube in the final step, thus preserving it from the\ninherent contaminations of nanofabrication and maintaining contact solely with\nsuperconducting electrodes and a crystalline hBN substrate. Through transport\nmeasurements performed in both the normal and superconducting states, we\ndemonstrate that our method yields high-quality junctions with Josephson\nenergies suitable for quantum device applications, such as carbon\nnanotube-based superconducting qubits.\n