Speaker
Description
The problem of dissipation in superconductors is associated with variations in time of the order parameter. In low-dimensions, the appearance of a finite voltage is related to the ac Josephson effect. It may lead to the observation of a charge current consisting simultaneously of superconducting and dissipative components. A notable example of such a phenomenon is the occurrence of phase slips in quasi-one-dimensional (quasi-1D) nanowires. We will present the results of our experiments on the current-voltage characteristics of superconducting films, in which finite voltages were applied along the length. These measurements reveal the existence of an electric-field-driven intermediate state. Its key feature is the propagation of a charge current with both zero-resistance and dissipative components. The electric field is found to penetrate over large distances of few hundred micrometres while signatures of superconductivity still persist. This provides a solid-state platform for probing the physics of nonequilibrium structures in a charged quantum fluid. We will discuss how the observations vary across quasi-1D and 3D specimens.