Role of long-range interactions in the melting of a metallic surface.

Abstract

Ion-shadowing and -blocking studies of melted layers on the (110) surface of Pb reveal an increasing melt thickness with temperature, which follows first a logarithmic growth law \ensuremath{\Vert}ln(${T}_{m}$-T)\ensuremath{\Vert}, then asymptotically a power law (${T}_{m}$-T${)}^{\mathrm{\ensuremath{-}}r}$, with r=0.315\ifmmode\pm\else\textpm\fi{}0.015. The logarithmic and power-law growth result from short-range and long-range atomic interactions, respectively. The correlation length within the melted phase is determined to be ${\ensuremath{\xi}}_{l}$=0.63 nm and for the Hamaker constant we find W=(0.40\ifmmode\pm\else\textpm\fi{}0.05)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}21}$ J.