Superconducting Resonator with Composite Film for Quantum Information
Edward Tang, IQC
The full manipulation of a quantum system can endow us with the power of computing in exponentially increased state space without exponential growth of physical resources. In this thesis, we are dedicated to the developments in superconducting devices and layout design for their future applications in large-scale quantum computation.
Making use of proximity effect, we developed composite superconducting films for resonators in the application of low-temperature pulsed-ESR for quantum information processing. We compared the performance of superconducting resonators made from single Nb film with those of composite films, including Nb/NbN/Nb, TiN/tapering/NbN/tapering/TiN, and Al/Nb/Al. We found that the quality factor of resonators from Al/Nb/Al surpasses the previous best results from single Nb film under 0.35 T magnetic field. We also established a formula for evaluating the surface impedance of composite superconducting film.