Non-linear transport properties of superconducting nanostructures

Abstract

By solving the Bogoliubov-de Gennes equation self-consistently, we compute transport properties of a one dimensional superconducting island with a delta-function normal scatterer at the centre. The calculated I-V characteristics show significant structure, arising from the competition between scattering processes at the boundaries of the island and modification of the order parameter by quasi-particles and superflow. At a certain critical current, the order parameter exhibits a quasi-first-order transition to the normal state, smeared by the finite system size. At this point, the differential conductance is negative and can have a magnitude greater than 2e2/h, despite the fact that there is ..