Dependence of the crystal-liquid phase transition temperature on the size and shape of a nanocrystal

The dependence of the crystal-liquid phase transition (melting) temperature T-m on the size and shape of a nanocrystal with a free surface has been studied proceeding from the Lindemann criterion. It is shown that, with neglect of the surface pressure, the T-m value decreases with a reduction in the isomorphous nanocrystal size. The greater the nanocrystal shape deviation from cubic, the more pronounced the size dependence of T-m. With allowance for the surface pressure, the T-m value increases with decreasing nanocrystal size if the arising pressure compresses the crystal. If the surface pressure produces an extension of the crystal, the decrease in T-m with decreasing size becomes more pronounced. The surface pressure can both suppress and enhance the size-dependent T-m variations.