In search for the vortex charge and the Cooper pair mass

A novel experiment for determination of the charge related to vortices in thin superconducting film is proposed and a number of related experimental set-ups are also theoretically considered. The methods are based on the Torricelli-Bernoulli effect in superconductors and the phenomenology of the effect is briefly discussed. The vortex charge is expressed via the effective mass of the Cooper pairs, thus both parameters, inaccessible by now, could be simultaneously determined. The experiment would require layered metal-insulator-superconductor structures and standard electronics employed in kinetic measurements. The quality of the insulator-superconductor interface should be high enough as to allow for observation of electric field effects similar to those investigated in superconducting field-effect transistors. The development of layer-by-layer growth technology of oxide superconductors provides unique possibility for investigation of new fundamental effects in these materials. In particular, the structures necessary for determination of the vortex charge could be used to study the superconducting surface Hall effect, Bernoulli effect, the superfluid density, etc.. In conclusion, the systematic investigation of new effects in oxide superconductors is envisaged as an important part of the material science underlying the oxide electronics.Comment: final version, section on interface Hall currents in type-I MIS structure added; 12 pages, 3 figures, LaTeX; intended as contribution to the Proceedings of SPIE Vol. 4058 "Superconducting and Related Oxides: Physics and Nanoengineering IV", Orlando 200

Determination of density of states of thin high-TcT_c films by FET type microstructures

A simple electronic experiment with a field effect transistor type microstructure is suggested. The thin superconductor layer is the source-drain channel of the layered structure where an AC current is applied. It is necessary to measure the second harmonic of the source-gate voltage and third harmonic of the source-drain voltage. The electronic measurement can give the logarithmic derivative of the density of states which is an important parameter for fitting of parameters of the band structures.Comment: 3 pages, 1 figur