Abstract
Structures in the conductance which are periodic in bias voltage have been observed in very weakly coupled Bi2Sr2CaCu2Ox/W point-contact tunneling junctions. These reproducible features appear to result from geometrical resonances of the order parameter, as would be found in superconductor-normal multilayers, rather than from Coulomb-staircase or multiple-gap effects. The data and its analysis strongly suggest the validity of treating even microscopic properties of Bi2Sr2CaCu2Ox using multilayer models with geometrical parameters inferred from the placement and thicknesses of the CuO2 conductive sheets within the unit cell.