Superconducting NbN Nanowires and Coherent Quantum Phase-Slips in DC Transport

Abstract

A quantum current standard dual to the Josephson voltage standard has been trumpeted as a primary application for the phenomenon of coherent quantum phase-slips (CQPS) in superconducting nanowires, but it requires a dc transport geometry, distinct from the ring geometry in which CQPS have been probed by microwave spectroscopy measurements. We present measurements on NbN nanowires with a width of 15 nm and including integrated thin-film resistors to provide a high-impedance environment. Analysis shows that the nanowire behavior is in line with expectations. The results demonstrate that the process is promising both for future dc transport CQPS measurements and for the fabrication of other circuits in which low-width superconducting nanowires are required.