Berlin 2008 – wissenschaftliches Programm
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SYMS: Symposium Modern developments in multiphysics materials simulations
SYMS 2: Modern developments in multiphysics materials simulations II - Poster (joined by SYEC posters)
SYMS 2.4: Poster
Donnerstag, 28. Februar 2008, 18:30–19:30, Poster F
A Hybrid Modelling Approach for the Structural Evolution of Stepped Surfaces — •Sibylle Gemming1, Julia Kundin2, Chol-Jun Yu2, Maria Radke de Cuba2, and Heike Emmerich2 — 1Forschungszentrum Dresden-Rossendorf, D-01314 Dresden, Germany. — 2Inst. f. Gesteinshüttenkunde und Center for Computational Engineering Science, RWTH Aachen, D-52064 Aachen, Germany.
The Burton-Cabrera-Frank (BCF) model describes the structural evolution of vicinal surfaces in terms of an incoming particle flux and concentration-dependent desorption and surface diffusion terms. A continuum formulation of the BCF scheme given by a phase-field implementation for the moving-boundary problem yields the long-term evolution of the step structure during a step-flow growth mode. A particle-based Ising-type approach with a Metropolis-Monte-Carlo kinetics additionally provides nucleation processes in a temperature-controlled manner and on a shorter time and length scale. We have integrated both approaches in a hybrid algorithm, which describes adsorption, nucleation, and structure evolution processes at solid-liquid and solid-gas interfaces on both time and length scales. The short-term nucleation is resolved by the Monte-Carlo generated dynamics of an anisotropic Ising model, whose interaction parameters stem from first-principles calculations. The long-term microstructure dynamics is calculated by the phase-field method. Several growth modes are distinguished: In addition to step-flow growth the nucleation processes on the terraces can lead to roughening or an epitaxial layer-by-layer growth controlled by temperature and by flux.