Spatial correlation in 2D and 3D thin films of conserved binary mixtures in the presence of wetting of substrates by the preferred majority component: interpretation in real scenario

Abstract

The spinodal decomposition has got fresh attraction in the past few decades with the advent of new computational problems under very thin geometries. The nanodrops evolve in the phase separation process. The phase separation process itself interplays with the wetting forces and give rise to structures of importance for a wide range of technological applications from spherical nanomagnetic domains to magnetic strips. MC simulation programs for 2D and 3D cases have been written for surface directed phase separation (using metropolis algorithm) to observe the spatial correlation varying with time, which shows a polynomial fitting behavior for 2D case and follow a peculiar trend with time specially, in early stages of evolution indicating a colossal behavior. The two point correlations (Pearson’s linear xy correlation function) if evaluated in 3D case do not show any important oscillatory behavior but instead confirm for the two regimes as phase separation or mixing and the wetting ones. The correct generalization of xy correlation as xyz correlation in 3D case (i.e., product of the three moments) does not seem to be a reliable one because it moves to six to seven decimal places, thus comes out at the cost of loss in confidence limit. Thus, the 3D simulation confirm the two regime behavior indicating that the same colossal behavior of 2D case can exist in real 3D thin film of random binary mixture. Thus, the colossal behavior as obtained for the case of 2D problem is retained, and this may indicate for a quantized or discrete colossal behavior for certain set of composition and interface parameters for definite but small time periods. The corresponding density profiles are also plotted to confirm the distributions of the two components. Such computational studies may help in developing theoretical models for the observed phenomena and to search out for new events at the very bottom of the scale.