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

摘要

We have produced Sn/Si core-shell cluster assemblies by aplasma-gas-condensation cluster beam deposition apparatus. For the sample withSi content = 12 at.%, the temperature dependence of electrical resistivityexhibits a metallic behavior above 10K and the onset of superconductingtransition below 6.1 K. With decreasing temperature, the thermomagnetic curvefor the sample with Si content = 8 at.% begins to decrease steadily towardnegative value below 7.7 K, indicating the Meissner effect. An increase in thetransition temperature, TC is attributable to exciton-typesuperconductivity.