Developing high-impedance superconducting resonators and on-chip filters for semiconductor quantum dot circuit quantum electrodynamics

Abstract

Spin-photon coupling presents an enticing opportunity for the long-range coupling of spin qubits. The spin-photon coupling rate $g_s$ is proportional to the charge-photon coupling rate $g_c$. To move deeper into the strong coupling regime, $g_c$ can be enhanced by fabricating high-impedance cavities using high kinetic inductance films. Here we report dc transport and microwave response investigations of niobium nitride (NbN) films of different thicknesses. The kinetic inductance increases rapidly as the film thickness is reduced below 50 nm and for 15 nm NbN films we measure a sheet kinetic inductance $L_{k,S}$ = 41.2 pH/$\square$. As an application of the high kinetic inductance films, we fabricate compact LC filters that are commonly used to reduce microwave leakage in circuit quantum electrodynamics (cQED) devices. These filters feature up to 60 dB of attenuation near typical cavity resonance frequencies $f_c$ = 8 GHz.

References in corpus (7)

• Circuit Quantum Electrodynamics with a Spin Qubit
• Strong Coupling Cavity QED with Gate-Defined Double Quantum Dots Enabled by a High Impedance Resonator
• Superconducting properties and Hall Effect of epitaxial NbN thin films
• Circuit Quantum Electrodynamics Architecture for Gate-Defined Quantum Dots in Silicon
• Universal scaling of the critical temperature for thin films near the superconducting-to-insulating transition
• Magnetic field resilient high kinetic inductance superconducting niobium nitride coplanar waveguide resonators
• On-chip microwave filters for high-impedance resonators with gate-defined quantum dots

Cited by in corpus (4)

• Cavity-mediated entanglement of parametrically driven spin qubits via sidebands
• Strong Charge-Photon Coupling in Planar Germanium Enabled by Granular Aluminium Superinductors
• High-impedance resonators for strong coupling to an electron on helium
• High-efficiency microwave photodetection by cavity coupled double dots with single cavity-photon sensitivity