Consistent calculation of boundary effects in thin superconducting films

Calculations of the critical transition temperature Tc of thin film superconductors are made using boundary conditions that satisfy the Friedel sum rule and allow electron penetration beyond the ion cores of the surface. Tc is found to decrease near the film surface, giving general agreement with experimental dispersions of Tc for thin films after a semi-empirical correction for granular film structure is included. 10 refs.