Discrete and Continuum Relaxation Dynamics of Faceted Crystal Surface in Evaporation Models
| Autor: | Dionisios Margetis, Kanna Nakamura |
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| Rok vydání: | 2013 |
| Předmět: |
Physics
Continuum (measurement) Differential equation Ecological Modeling Kinetics Rotational symmetry General Physics and Astronomy General Chemistry Concentric Computer Science Applications Classical mechanics Modeling and Simulation Free boundary problem Boundary value problem Microscale chemistry |
| Zdroj: | Multiscale Modeling & Simulation. 11:244-281 |
| ISSN: | 1540-3467 1540-3459 |
| Popis: | We study linkages of two scales in the relaxation of an axisymmetric crystal with a facet in evaporation-condensation kinetics. The macroscale evolution is driven by the motion of concentric circular, repulsively interacting line defects (steps) which exchange atoms with the vapor. At the microscale, the step velocity is proportional to the variation of the total step free energy, leading to large systems of differential equations for the step radii. We focus on two step flow models. In one model (called M1) the discrete mobility is simply proportional to the upper-terrace width; in another model (M2) the mobility is altered by an extra geometric factor. By invoking self-similarity at long time, we numerically demonstrate that (i) in M1, discrete slopes follow closely a continuum thermodynamics approach with “natural boundary conditions” at the facet edge; (ii) in contrast, predictions of M2 deviate from results of the above continuum approach; and (iii) this discrepancy can be eliminated via a continuum ... |
| Databáze: | OpenAIRE |
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