Melting of superheated crystals initiates on vacancies

摘要

In a large variety of ideal crystals we found that when rapidly migratingatoms squash or annihilate a neighbouring vacancy and produce a disorderedcluster, the heat of migration stored in the system exceeds the enthalpyincrease required for the coordinating atoms of the vacancy to form a liquidphase, i.e. the liquid phase nucleates from vacancies. Furthermore volumetricanalysis supports this well. This vacancy-decomposition model providesquantitative information on the melting point, the latent heat and the volumechange upon melting and hence clarifies the mechanism of melting.