Single crystals of Bi2Sr2CaCu2Ox with transition temperatures of 85 K
have been studied using a low temperature scanning, tunneling microsop
e. Spectra of very weakly coupled point contact configuration have bee
n obtained and reproducible periodic conductance structures in the bia
s voltage have been found. A model based on geometrical resonances in
superconducting superlattice is proposed and found to provide a satisf
actory explanation of the data.