Effects of surface topography on the collective diffusion of interacting adsorbed particles

• Collective diffusion of interacting particles adsorbed on heterogeneous surfaces.
• Bivariate surface of adsorptive patches with a characteristic correlation length ll.
• A rich variety of structural orderings were observed in the adlayer.
• Transport coefficients are strongly affected by surface topography and ad–ad couplings.

Collective diffusion of particles with repulsive nearest-neighbor interactions on bivariate surfaces is studied through Monte Carlo simulation, in the framework of the Kubo–Green theory. Shallow and deep adsorbing sites form l×ll×l patches distributed at random or in chessboard-like ordered domains on a two-dimensional square lattice. The influence of the energetic correlation and the lateral interactions on the jump and collective diffusion coefficients are analyzed by simulating the coverage fluctuations in the grand canonical ensemble and the mean-square displacements of particles in the canonical ensemble. The combination of topography and lateral coupling is shown to produce interesting effects such as different filling regimes as well as strong effects on the coverage dependence of the transport coefficients.