Entropy for solid-liquid transition in nanocrystals

It is demonstrated that a simple model, free of any adjustable parameter, can be developed for the melting entropy of nanocrystals based on Mott's equation for the melting entropy and a model for the size-dependent melting. It is shown that the entropy of melting for a nanocrystal decreases as size decreases, suggesting that the difference in the degree of order between the liquid and solid phase is size-dependent. Supported by both the available experimental results on Sn and Al nanocrystals and the first principle calculations on Al nanocrystals, the model suggests that the size dependence of the entropy of melting for non-semiconductor nanocrystals is determined by the size dependence of vibrational component of the melting entropy. (C) 1998 Elsevier Science B.V. All rights reserved.