Current–voltage characteristics of superconductor-normal metal-superconductor junctions

We develop a theory of current–voltage (I-U) characteristics for superconductor-normal metal-superconductor (SNS) junctions. At small voltages and sufficiently low temperatures the I-U junction is controlled by inelastic relaxation time τin. In particular, linear conductance proportional to this regime can be expressed solely in terms dependence density states normal region ν(χ) on phase difference order parameter across junction. contrast, at large device elastic τel, which much smaller than one.