A Stochastic SPICE Model for Superconducting Nanowire Single Photon Detectors and Other Nanowire Devices

Superconducting nanowire devices, such as the superconducting nanowire single photon detector (SNSPD) or nanocryotron, have a time-dependent stochasticity that depends on the current flowing through them. When modeling complex circuits made of several such devices (for instance, an array of SNSPDs), the ability to include this randomness can be important for predicting unwanted effects and interactions within the circuit. We present a modification of the model described by Berggren et al. that allows for the inclusion of this stochasticity into the nanowire device model. We then verify the model against experiment using a tungsten silicide SNSPD, and show that the modified model replicates the stochasticity of the physical device.