Interplay between thermal percolation and jamming upon dimmer adsorption on binary alloys

LOSCAR, E. S.; RODOLFO ALBERTO BORZI; ALBANO, E. V.

Physical Review E - Statistical Physics, Plasmas, Fluids and Related Interdisciplinary Topics

Año: 2006 vol. 74 p. 1 - 1

By means of Monte Carlo simulations we study jamming and percolation processes upon the randomsequential adsorption of dimers on binary alloys with different degrees of structural order. The substrates areequimolar mixtures that we simulate using an Ising model with conserved order parameter. After an annealingat temperature T we quench the alloys to freeze the state of order of the surface at this temperature. Thedeposition is then performed neglecting thermal effects like surface desorption or diffusion. In this way, theannealing temperature is a continuous parameter that characterizes the adsorbing surfaces, shaping the depo-sition process. As the alloys undergo an order-disorder phase transition at the Onsager critical temperature Tc ,the jamming and percolating properties of the set of deposited dimers are subjected to nontrivial changes,which we summarize in a density-temperature phase diagram. We find that for T T* = 1.22Tc the occurrenceof jamming prevents the onset of percolating clusters, while percolation is possible for T T*. Particularattention is focused close to T*, where the interplay between jamming and percolation restricts fluctuations,forcing exponents seemingly different from the standard percolation universality class. By analogy with athermal transition, we study the onset of percolation using the temperature T as a control parameter. Wepropose thermal scaling Ansätze to analyze the behavior of the percolation threshold and its thermally inducedfluctuations. Also, the fractal dimension of the percolating cluster is determined. Based on these measurementsand the excellent data collapse, we conclude that the universality class of standard percolation is preserved forall temperatures.