Dynamics of superconducting nanowires shunted with an external resistor

We present a study of superconducting nanowires shunted with an external resistor, geared towards understanding and controlling coherence and dissipation in nanowires. The dynamics is probed by measuring the evolution of the V -I characteristics and the distributions of switching and retrapping currents upon varying the shunt resistor and temperature. Theoretical analysis of the experiments indicates that as the value of the shunt resistance is decreased, the dynamics turns more coherent, presumably due to stabilization of phase-slip centers in the wire, and furthermore the switching current approaches the Bardeen’s prediction for equilibrium depairing current. By a detailed comparison between theory and experiment, we make headway into identifying regimes in which the quasi-one-dimensional wire can effectively be described by a zero-dimensional circuit model analogous to the resistively and capacitively shunted Josephson junction model of Stewart and McCumber. Aside from its fundamental significance, our study has implications for a range of promising technological applications.