Magnetic field resilient high kinetic inductance superconducting niobium nitride coplanar waveguide resonators

• Published in: Applied physics letters Vol. 118; no. 5
• Main Authors: Yu, Cécile Xinqing, Zihlmann, Simon, Troncoso Fernández-Bada, Gonzalo, Thomassin, Jean-Luc, Gustavo, Frédéric, Dumur, Étienne, Maurand, Romain
• Format: Journal Article
• Language: English
• Published: American Institute of Physics 01-02-2021
• Subjects: Condensed Matter; Physics; Quantum Physics; Superconductivity
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/5.0039945

We characterize niobium nitride (NbN)
λ
/
2 coplanar waveguide
resonators, which were fabricated from a 10-nm-thick film on silicon dioxide grown by
sputter deposition. For films grown at 180 °C, we report a superconducting critical
temperature of 7.4 K associated with a normal square resistance of
1

k
Ω, leading to a kinetic
inductance of 192 pH/◻. We fabricated resonators with a characteristic
impedance up to
4.1

k
Ω and internal quality
factors
Q
i
>
10
4 in the single
photon regime at zero magnetic field. Moreover, in the many photon regime, the resonators
present a high magnetic field resilience with
Q
i
>
10
4 in a 6 T
in-plane magnetic field and in a 300 mT out-of-plane magnetic field. These findings make
such resonators a compelling choice for circuit quantum electrodynamics experiments
involving quantum systems with small electric dipole moments operated in finite magnetic
fields.