Surface melting of small crystals

Abstract Surface melting (the appearance of a quasi-liquid film on a crystal face) of a small crystal has been studied by means of phenomenological thermodynamics. The thickness of the quasi-liquid film is found to depend on the crystal size. The film is thicker for a small “negative” crystal and less thick for a “positive” crystal in comparison with the film formed on a large (planar) crystal. An equation, analogous to that of Thomson-Gibbs for the vapor pressure of small phases, is derived. An explanation of the lower roughering temperature of small “negative” crystals is offered.