Magnetic field resilient superconducting coplanar waveguide resonators for hybrid cQED experiments

TL;DR

This paper develops magnetic field resilient superconducting coplanar waveguide resonators using lithographic defects in NbTiN films, enabling stable high-quality resonances in strong magnetic fields for hybrid quantum systems.

Contribution

It introduces a method to enhance the magnetic field resilience of superconducting resonators through artificial defects and device geometry optimization, improving performance in high magnetic fields.

Findings

Resonators maintain quality factors ~10^5 up to 20 mT perpendicular magnetic field.

Resonators operate stably up to 6 T parallel magnetic field.

Successful integration with InSb nanowire for quantum dot charge readout at 1 T.

Abstract

Superconducting coplanar waveguide resonators that can operate in strong magnetic fields are important tools for a variety of high frequency superconducting devices. Magnetic fields degrade resonator performance by creating Abrikosov vortices that cause resistive losses and frequency fluctuations, or suppressing superconductivity entirely. To mitigate these effects we investigate lithographically defined artificial defects in resonators fabricated from NbTiN superconducting films. We show that by controlling the vortex dynamics the quality factor of resonators in perpendicular magnetic fields can be greatly enhanced. Coupled with the restriction of the device geometry to enhance the superconductors critical field, we demonstrate stable resonances that retain quality factors $\simeq 10^5$ at the single photon power level in perpendicular magnetic fields up to $B_\perp \simeq$ 20 mT and parallel magnetic fields up to $B_\parallel \simeq$ 6 T. We demonstrate the effectiveness of this technique for hybrid systems by integrating an InSb nanowire into a field resilient superconducting resonator, and use it to perform fast charge readout of a gate defined double quantum dot at $B_\parallel =$ 1 T.