Localization and interaction effects in ultrathin amorphous superconducting films

Abstract

Ultrathin superconducting films of amorphous Mo-Ge were made that remain homogeneous down to ∼20 Å. The expected localization behavior was observed in their resistivity-versus-temperature and sheet resistance ($R_{\square }$) data. A systematic reduction of the transition temperature with increasing $R_{\square }$ was observed for several compositions, consistent with recent theories of localization and Coulomb interaction effects on superconductivity. Critical-field data provide further tests of these theories.