Monte Carlo studies were made of the correlation factor of atoms diffusing via vacancies in nanofilms with a face-centered cubic crystal lattice. The thickness of the films, defined as the number of crystal lattices along the axis perpendicular to the film surface, and the average number of jumps per atom were key variables in the simulation. Different jump frequency ratios of surface and interior atom-vacancy exchanges were also varied to investigate their influences on the correlation factor. The correlation factor of atoms approached 0.781 when the film thickness was sufficiently large, which agrees well with the value for the 3D fcc bulk lattice. As the film thickness was reduced to a minimum, the factor converged to 0.467, a value for the 2D square lattice. Abrupt change of the correlation factor occurred at a few numbers of lattices, i.e., in the nanofilm regime, which was mainly due to the confinement of atoms to nanofilms and could also be analyzed mathematically.

Monte Carlo Simulation of Atoms Diffusion via Vacancies in FCC-Structured Nanofilms. Y.C.Chieh, F.H.Lu: Journal of Physics and Chemistry of Solids, 2008, 69[2-3], 315-9