ONE POSSIBLE MECHANISM FOR THE RESISTANCE INCREASE DUE TO SUPERCONDUCTING TRANSITION IN STRONGLY DISORDERED FILMS

In strongly disordered films with a thickness about few hundred angstroms and a very high sheet resistance 1-100 M OMEGA (granular aluminum films, quench condensed Hg-films etc.) a superconducting transition leads to a significant increase of the films resistance. In this report we want to suggest the possible explanation of this effect. The main idea is that such films are two-dimensional entities from the point of view of the normal state conductivity, but, on the other hand, they must be consider as three-dimensional objects to discuss their superconducting properties because a superconducting coherence length is smaller than the films thickness. These films are non-homogeneous and it is possible that only small regions of the sample are superconductors. In this case, small superconducting particles randomly distributed through the sample should increase the film non-homogeneity and it has to enhance the localization of electrons.