SCALING IN LATE-STAGE SPINODAL DECOMPOSITION WITH QUENCHED DISORDER

We study the late stages of spinodal decomposition in a Ginzburg-Landau mean held model with quenched disorder. Random spatial dependence in the coupling constants is introduced to model the quenched disorder. The effect of the disorder on the scaling of the structure factor and on the domain growth is investigated in both the zero temperature limit and at finite temperature. In particular, we find that at zero temperature the domain size R(t) scales with the amplitude A of the quenched disorder as R(t) = A(-beta) f(t/A(-gamma)) with beta similar or equal to 1.0 and gamma similar or equal to 3.0 in two dimensions. We show that beta/gamma = alpha, where alpha is the Lifshitz-Slyosov exponent. At finite temperature, this simple scaling is not observed and we suggest that the scaling also depends on temperature and A. Comparisons of the scaled structure factors for all values of A at both zero and finite temperature indicate only one universality class for domain growth. We discuss these results in the context of Monte Carlo and cell dynamical models for phase separation in systems with quenched disorder and propose that in a Monte Carlo simulation the concentration of impurities c is related to A by A similar to c(1/d).