Surface structure and surface diffusion: The fcc (110)interface

The structure of the (110) crystal-vapor or crystal-melt interface of an fcc crystal has been calculated in zeroth order approximation. The results indicate that structural roughening of the interface occurs in the range 0.03 kT / L kT / L . Here L is the enthalpy of vaporization or melting and T is the absolute temperature. The relative population of surface energy levels has also been computed. For kT / L > 0.3, the surface approximates an ideally rough configuration. The surface self diffusion coefficient has been computed from the theoretical distribution of atoms at the interface. The results indicate a positive departure from Arrhenius behavior in the temperature interval where roughening occurs. In the L / kT range encountered in metal-vapor systems the theoretically obtained log ( D s versus L / kT relationship is linear. The departure from linearity commonly observed in fcc metal-vapor system is therefore not predicted to be the result of structural roughening of the (110) orientation surface.