Possibility of Exciton Mediated Superconductivity in Nano-Sized Sn/Si Core–Shell Clusters: A Process Technology towards Heterogeneous Material in Nano-Scale

Abstract

We have produced Sn/Si core–shell cluster assemblies by a plasma-gas-condensation cluster beam deposition apparatus. For the sample with Si content = 12 at. %, the temperature dependence of electrical resistivity exhibits a metallic behavior above 10 K and the onset of superconducting transition below 6.1 K. With decreasing temperature, the thermomagnetic curve for the sample with Si content = 8 at. % begins to decrease steadily toward negative value below 7.7 K, indicating the Meissner effect. An increase in the transition temperature, TC is attributable to exciton-type superconductivity.