Random telegraph fluctuations in granular microwave resonators

Abstract

Microwave circuit electrodynamics of disordered superconductors is a very active research topic spawning a wide range of experiments and applications. For compact superconducting circuit elements, the transition to an insulating state poses a limit to the maximum attainable kinetic inductance. It is therefore vital to study the fundamental noise properties of thin films close to this transition, particularly in situations where a good coherence and temporal stability is required. In this paper, we present measurements on superconducting granular aluminum microwave resonators with high normal state resistances, where the influence of the superconductor to insulator phase transition is visible. We trace fluctuations of the fundamental resonance frequency and observe, in addition to a 1/f noise pattern, a distinct excess noise, reminiscent of a random telegraph signal. The excess noise shows a strong dependency on the resistivity of the films as well as the sample temperature, but not on the applied microwave power.

6 pages, 4 figures

References in corpus (14)

• Localization of preformed Cooper-pairs in disordered superconductors
• Nature of the superconductor-insulator transition in disordered superconductors
• Decoherence benchmarking of superconducting qubits
• Efficient and robust analysis of complex scattering data under noise in microwave resonators
• Number fluctuations of sparse quasiparticles in a superconductor
• The Higgs Mode in Disordered Superconductors Close to a Quantum Phase Transition
• Quantum breakdown of superconductivity in low-dimensional materials
• Generalized Tunneling Model for TLS in amorphous materials and its predictions for their dephasing and the noise in superconducting microresonators
• Electrodynamics of granular aluminum from superconductor to insulator: observation of collective superconducting modes
• Microwave-induced excess quasiparticles in superconducting resonators measured through correlated conductivity fluctuations
• Optical signatures of the superconducting Goldstone mode in granular aluminum: experiments and theory
• Direct observation of the superconducting gap in thin film of titanium nitride using terahertz spectroscopy
• Microwave properties of superconductors close to SIT
• Universal Voltage Fluctuations in Disordered Superconductors