Monte Carlo simulation was employed to investigate correlation factors of atoms (fA) diffusing via vacancies in nanofilms possessing a simple cubic lattice that was selected as a model system. The correlation factors changed significantly upon varying the film thickness, as well as jump frequency ratios. When the film thickness was sufficiently large, fA approached 0.6531, a limiting value for the 3D bulk lattice. As the film thickness was quite small, fA converged to 0.4669, a limiting value for the 2D square lattice. A minimum of the factors, corresponding to 2/3 x fA(3D-SC) (= 0.4354), occurred in a specific nanofilm regime ranging from about 100 to 500 atomic layers, which was due mainly to confinement of atom movement to nanofilms. Correlation factors of vacancy diffusion (fv) were also investigated and exhibited similar trends in the relationship between the factors and the film thickness in a certain nanofilm regime.

Monte Carlo Simulation of Atom Diffusion via Vacancies in Nanofilms with a Model Simple Cubic Lattice System. Y.C.Chieh, F.H.Lu: Journal of Nanoscience and Nanotechnology, 2011, 11[3], 2376-83