Localization and magnetic-field-enhanced superconductivity in thin films of Au-Ge

Magnetic-field-enhanced superconductivity is observed above the zero field critical temperatures Tc0 under parallel magnetic fields(Tc-enhancement) in alloy-films of Au and Ge around the film thickness of 2nm. The origin of this Tc-enhancement is ascribed to a quantum compensation of orbital depairing. The field(H)-dependence of the critical temperatures Tc is described by (Tc -Tc0)/Tc0 = H2{a + b[log ((H2 + H2i)/H2i)]}, where Hi is the effective inelastic scattering field, a contains the effect of Tc-enhancement and b is attributed to the localization effect in a two dimensional film with a strong spin orbit scattering. (orig.)