Spatial Variation of Superconducting Order Parameters in Thin Aluminum Films

The oscillations of the order parameter arising due to the spatial quantization of electronic states in a quantum well formed by the boundaries of a thin film of superconducting aluminum were theoretically studied. In such objects, with decreasing thickness, a noticeable increase in the critical temperature and broadening of the superconducting transition are observed. These effects are interpreted as a manifestation of the quantum size effect that affects the density of states of electrons and, hence, other various electronic properties of thin films.