Discrete periodic melting point observations for nanostructure ensembles

We report a study of the thermodynamic properties of indium clusters on a S iNx surface during the early stages of thin film growth using a sensitive n anocalorimetry technique. The measurements reveal the presence of abnormal discontinuities in the heat of melting below 100 degreesC, These discontinu ities, for which temperature separation corresponds to a spatial periodicit y equal to the thickness of an indium monolayer, are found to be related to the atomic "magic numbers," i.e., the number of atoms necessary to form a complete shell of atoms at particle surface.