MELTING PROPERTIES OF FCC METALS USING A TIGHT-BINDING POTENTIAL

Using a constant-pressure Monte Carlo simulation we study the melting properties of fee metals described by a second-moment tight-binding po tential. We find good agrement with experimental melting temperature f or lead (Pb) and a reasonable prediction for noble and transition meta ls. This was done by changing only an overall energy scale. The local structure of the metal below the melting point is distorted with respe ct to the perfect solid-phase structure. We associate the distortion w ith the appearance of defects in the crystalline phase which act as th e precursor of the melting. The liquid has a considerable structure ab ove the melting temperature which resembles the local structure of the solid. At higher temperatures where diffusional dynamics is activated the liquid loses its local structure. Our results suggest that the el astic instability alone cannot be responsible for the melting.