Niobium nitride (NbN) is a particularly promising material for quantum technology applications, as entails the degree of reproducibility necessary for large-scale of superconducting circuits. We demonstrate that resonators based on NbN thin films present a one-photon internal quality factor above 105 maintaining a high impedance (larger than 2kΩ), with a footprint of approximately 50x100 μm2 and a self-Kerr nonlinearity of few tenths of Hz. These quality factors, mostly limited by losses induced by the coupling to two-level systems, have been maintained for kinetic inductances ranging from tenths to hundreds of pH/square. We also demonstrate minimal variations in the performance of the resonators during multiple cooldowns over more than nine months. Our work proves the versatility of niobium nitride high-kinetic inductance resonators, opening perspectives towards the fabrication of compact, high-impedance and high-quality multimode circuits, with sizable interactions.
@article{arxiv.2302.13930,
title = {High-kinetic inductance NbN films for high-quality compact superconducting resonators},
author = {Simone Frasca and Ivo Nikolaev Arabadzhiev and Sebastien Yves Bros de Puechredon and Fabian Oppliger and Vincent Jouanny and Roberto Musio and Marco Scigliuzzo and Fabrizio Minganti and Pasquale Scarlino and Edoardo Charbon},
journal= {arXiv preprint arXiv:2302.13930},
year = {2023}
}