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Monte‐Carlo program for simulating segregation and diffusion utilizing chemical potential calculations
Author(s) -
Joubert H. D.,
Swart H. C.,
Terblans J. J.
Publication year - 2004
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.1915
Subject(s) - kinetic monte carlo , monte carlo method , diffusion , thermodynamics , atom (system on chip) , gibbs free energy , chemical physics , materials science , potential energy , surface layer , kinetic energy , statistical physics , layer (electronics) , chemistry , atomic physics , physics , nanotechnology , classical mechanics , statistics , mathematics , computer science , embedded system
The surface segregation phenomenon was simulated by means of a Chemical Potential Monte‐Carlo (CPMC) model, which is based on the Darken model. The chemical potential equations are rewritten to include the segregation energy associated with the surface layer. Simulations involving the change in chemical potential are performed on a two‐dimensional matrix containing two elements: the solute and the solvent elements. A random selection of an atom inside the matrix initiates the model. The change in chemical potential due to an atomic jump of a randomly selected atom to an adjacent layer is calculated. The largest change in chemical potential directs the atomic motion, complying with the conditions associated with lowering of the Gibbs free energy. Inclusion of the segregation energy (for jumps involving the surface layer) limits the number of atomic jumps from the surface layer to the bulk. Simulated segregation profiles generated by the CPMC model were compared with profiles calculated with both the modified Darken and Fick models. These profiles show that the CPMC model successfully describes both the kinetic and equilibrium conditions associated with surface segregation. Copyright © 2004 John Wiley & Sons, Ltd.