The objective of the project is the understanding of phenomena characteristic of granular and connected superconductors. As an original approach, this study is pursued with the aid of well controlled super conducting 2D networks. In a super conducting network it is possible to control, through the micro and sub micro-fabrication, all the characteristics of the system: the super conducting coupling, the disorder, the relevance of the charging effect and the role of the electrical potential in the 2D coulomb gas regime, the role of the magnetic field and that of the mutual and self inductance in the high temperature regime. In particular the network is intended to investigate fundamental phenomena like: ground state configurations, coherence, flux pinning, behaviour of ballistic vortices, vortex interaction, quantum fluctuations. The project methodology includes Nanoscale fabrication, microscopic studies of the ground state by means of Bitter decorations and of the dynamics by means of the Low Temperature SEM, very sensitive investigations of the kinetic inductance and finally highly sophisticated computer simulations of both the low temperature and the high temperature regimes.
The project has investigated phenomena characteristic of granular and connected superconductors with the aid of well controlled superconducting 2-dimensional networks. Results are as follows:
fabrication of JJ arrays, superconducting wires and hybrid systems;
fabrication of high critical temperature (Tc) wire arrays showing macroscopic flux quantification;
first bitter decoration of an array of superconducting wires;
microscopic detection of the vortex dynamics in arrays of overdamped and underdamped junctions;
determination of the ground state in triangular and fractal lattices;
study of the ballistic vortex dynamics and of the charge vortex duality, relevant to quantum electronics;
medium scale computer facility for the investigations of quantum phenomena that can be described using path integral methods, many body theory, etc;
medium scale computer facility with optimized programs for the investigation of the static and the dynamic behaviour of both RSJ and CRSJ arrays with full screening correction.
Funding SchemeCSC - Cost-sharing contracts
2600 GA Delft