Frequency Pulling and Mixing of Relaxation Oscillations in Superconducting Nanowires

Abstract

The electromagnetic response of a superconducting nanowire exhibits relaxation oscillations, due to strong electrothermal nonlinearity. Resultant technology has been limited, though, by a lack of understanding of how the nonlinear behavior can be externally modulated. This study of electrothermal oscillations in superconducting nanowires uses microwave modulation to show that the oscillations mix with an external microwave drive, and lock to its frequency. This interaction is reminiscent of the ac Josephson effect, despite its thermal origin. Nanowire devices based on these phenomena could see use in microwave applications like frequency mixing and parametric amplification.