High-Quality-Factor High-Kinetic-Inductance Superconducting NbN Resonators for use in Strong Magnetic Fields
ORAL
Abstract
High-kinetic-inductance (high-Lk) superconducting resonators are a key component for hybrid quantum systems used in quantum computing and quantum sensing. However, achieving high quality factors remains challenging, as the disordered materials required for the low coherence length of high-Lk also host two-level systems (TLS) that increase dielectric losses at low power [1]. Earlier studies showed internal quality factors (Qi) > 105 in the single photon regime and similar values in strong magnetic fields for high-Lk materials [1, 2, 3, 4, 5, 6].
In this study, we aimed to achieve field resilient high-Q resonators by fabricating and measuring λ/4 coplanar waveguide resonators using superconducting high-Lk sputtered niobium nitride (NbN). We explored various geometries to investigate participation ratios of interface TLS and analyse their respective contribution with electrostatic simulations. We systematically measure Qi in excess of 105 in the single photon regime. We also show the ability to maintain internal quality factors above 104 up to 1 T of in-plane magnetic field in the many photons regime. This study of TLS losses and magnetic field properties yields promising results for the use of high-Lk NbN resonators in hybrid quantum systems.
[1] arXiv:2503.13321 (2025)
[2] Phys. Rev. Applied 11, 064053 (2019)
[3] Appl. Phys. Lett. 124, 114004 (2024)
[4] Phys. Rev. Applied 5, 044004 (2016)
[5] Phys. Rev. Applied 20, 044021 (2023)
[6] IEEE Trans. Appl. Supercond. 35 0601116 (2025)
In this study, we aimed to achieve field resilient high-Q resonators by fabricating and measuring λ/4 coplanar waveguide resonators using superconducting high-Lk sputtered niobium nitride (NbN). We explored various geometries to investigate participation ratios of interface TLS and analyse their respective contribution with electrostatic simulations. We systematically measure Qi in excess of 105 in the single photon regime. We also show the ability to maintain internal quality factors above 104 up to 1 T of in-plane magnetic field in the many photons regime. This study of TLS losses and magnetic field properties yields promising results for the use of high-Lk NbN resonators in hybrid quantum systems.
[1] arXiv:2503.13321 (2025)
[2] Phys. Rev. Applied 11, 064053 (2019)
[3] Appl. Phys. Lett. 124, 114004 (2024)
[4] Phys. Rev. Applied 5, 044004 (2016)
[5] Phys. Rev. Applied 20, 044021 (2023)
[6] IEEE Trans. Appl. Supercond. 35 0601116 (2025)
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Presenters
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Yannick Lapointe
- Université de Sherbrooke