Berlin 2005 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

DY: Dynamik und Statistische Physik

DY 44: Growth and Fracture

DY 44.4: Vortrag

Dienstag, 8. März 2005, 16:30–16:45, TU H3010

Faceting and coarsening of a crystal surface — •Frank Hausser and Axel Voigt — Crystal Growth Group, Froschungszentrum caesar, Ludwig-Erhard-Allee 2, 53175 Bonn

The faceting and coarsening of a growing crystal surface caused by strongly anisotropic surface tension is studied. The dynamics is driven either by surface diffusion accompanied by a depositon flux normal to the interface or by attachment kinetics. In both cases the highly nonlinear evolution equations are derived from a curvature dependent surface energy.

We present detailed numerical studies for 1-dimensional surfaces. For both models, two stages in the formation of facets are found: at a first stage, a rather periodic hill-valley structure is formed. At the second stage three distinct morphologies emerge, depending on the growth rate of the surface: either faceting and subsequent coarsening occurs, or a periodic (faceted) pattern emerges, or the surface becomes rough. Moreover, in the first case, the only coarsening event is a kink ternary, i.e. a coalescence of two kinks and one antikink resulting in a kink. Also, the coarsening rate is shown to obey a power law. This results are in agreement with predictions based on a low dimensional dynamical system.