Shape, Structural, and Energetic Effects on the Cohesive Energy and Melting Point of Nanocrystals

Abstract

A nonlinear, lattice type-sensitive model, free of any adjustable parameter, has been developed to account for the shape and size dependency of the cohesive energy of free-standing nanocrystals (nanoparticles, -wires, and -films). In this model, the effects of the averaged structural and energetic properties of the surface and the volume of nanocrystals along with the first and second nearest-neighbor atomic interactions have been taken into consideration and gathered in a new parameter named as the surface-to-volume energy contribution ratio. This model has been compared to the experimental data of the cohesive energy of W and Mo nanoparticles, and the melting points of Au, Pb, Al, and Sn nanoparticles and Pb and In nanofilms. Moreover, the model has been corrected to account for the effect of substrate on the melting point of substrate-supported Sn nanodisks. It has been found that the present model has generally a good agreement with those experimental data measured by different techniques under different experimental conditions.