MORPHOLOGY OF PERIODIC SURFACE PROFILES BELOW THE ROUGHENING TEMPERATURE - ASPECTS OF CONTINUUM THEORY

Using a simple analytical form of the anisotropic surface free energy, gamma(theta), the quasi-stationary shape of one-dimensional periodic surface profiles below the roughening temperature as well as the kinetics of profile decay are calculated numerically. With the macroscopic surface being close to a cusp orientation in gamma(theta), all profiles exhibit extended flat regions at the top and bottom (facets). These same regions and their adjacent rounded parts are near equilibrium, as a comparison with the truncated equilibrium shape of small particles for the same gamma(theta) shows. The facet size of the profile depends on the total anisotropy of gamma(theta) in the zone of interest, and on the amplitude of the profile. These dependences can also be simulated by the equilibrium construction. The gamma(theta) function used in this study is examined in relation to the more fundamental expression for the anisotropic surface free energy and also experimental data for Pb. It is found to fit these experimental data very well over a large range of orientations.