Local superconductivity in ultrathin Sn films

Abstract
The thickness dependence of superconductivity has been investigated in ultrathin Sn films near the threshold for normal-state conduction. An evolution from insulating to metallic superconducting behavior is observed with increasing thickness and decreasing sheet resistance. A striking feature of the data is the observation of quasireentrant superconductivity which may be a consequence of the existence of local rather than global superconducting order.