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Inverse a-c Josephson effect at terahertz frequencies

Technical Report ·
OSTI ID:5486805

The inverse a-c Josephson effect occurs when a Josephson junction driven by a microwave source of frequency f produces constant-voltage steps at integer multiples of hf/2e. For low leakage current, hysteretic junctions driven at microwave frequencies below about 100 GHz, some of these steps can cross the zero dc bias current axis. These zero-crossing steps allow modern-series array-voltage standards to operate without individually biasing the junctions in the array. The authors r-eexamine the theory behind these steps and show that they can exist at frequencies much higher than thought previously; the Riedel singularity in the supercurrent response allows this effect to exist even up to terahertz frequencies. They describe a set of analytical calculations that provide limits on the amount of rounding of the Riedel Peak that can be permitted while still allowing these zero-crossing steps to occur. They also discuss practical considerations such as microwave power levels required and parameters for device fabrication. This analysis is supported by numerical frequency-domain computations and time-domain simulations for a number of realistic I-V curves with rounded Riedel singularities and with quasi-particle subgap leakage currents.

Research Organization:
California Univ., Berkeley, CA (USA)
OSTI ID:
5486805
Report Number(s):
AD-A-210860/3/XAB
Country of Publication:
United States
Language:
English