THERMAL FLUCTUATIONS OF AN ATOMICALLY SMOOTH CRYSTAL-SURFACE

The contribution of fluctuation-induced nucleation centers (projections and depressions on the atomically smooth face of a crystal) to the correlation functions of the surface displacements is considered. It is shown that for the surface of a three-dimensional crystal the excitations should lead to a spatial correlation function which differs from the Ornstein - Zernicke law as in the case of the two-dimensional Ising model. Due to the large lifetime they may also determine the equilibrium dynamics of an atomically smooth surface and lead to a nonexponential decrease of the temporal correlations. For the surface of a three-dimensional crystal the corresponding autocor-relation function for large time periods t is proportional to exp(-const.t1/2).