Analysis of molecular-dynamics simulations of the (111) surface of germanium crystal near its bulk melting temperature

Abstract

A molecular-dynamics (MD) simulation of the Ge(111) surface within 2% of the Ge bulk melting temperature $T_m$ has been analyzed statistically, and the results have been applied in a discussion of low-energy electron diffraction (LEED) observations of disordering at Ge(111). MD results indicate that long-range disordering occurs only on laterally compressed model crystals. An analysis of vibrational disorder in regions retaining local crystalline order confirmed the applicability of the Debye-Waller theory to LEED from Ge near $T_m$. Calculations of the positional pair-correlation function indicated that, in regions where crystalline order is absent, the surface structure is that of a two-dimensional liquid layer with some degree of periodic density modulation.