INHERENT AMORPHOUS STRUCTURES AND STATISTICAL-MECHANICS OF MELTING

The statistical mechanics of local and global order in a condensed sys tem is studied in a coarsened model in which the atomic arrangements i n small volumes may be crystalline or amorphous. The melting behavior of the material is determined by two characteristic energies, the ener gy of an orientationally disordered locally crystalline state and the energy of a completely amorphous state. If the amorphization energy is high, the material retains local crystallinity even in the melt; then , at higher temperatures there is a crossover to a locally amorphous s tate. A material with a low-energy noncrystalline local packing exhibi ts amorphization melting; the phase transition is from an orientationa lly ordered crystal state to a fully amorphous melt. Strong interactio ns that are not of a two-body type are suggested to favor the first be havior, and to lead to structural liquids just above the melting point . (C) 1997 American Institute of Physics.