Growth kinetics in two-dimensional binary mixtures with bond-disorder: Monte Carlo simulation results Samiksha Shrivastava and Awaneesh Singh* Department of Physics, Indian Institute of Technology (BHU), Varanasi-221005, India Abstract The evolving domain structures in phase separating mixtures can significantly influence the final properties of materials. We present here the effect of quenched disorder (in the form of bond-disorder) on the kinetics of phase separating binary () mixtures. Our particular focus is on the domain structure, phase behavior, growth laws, and dynamical scaling. The bond disorder (BD), which acts as an impurity in the system, is introduced in a regular manner. To model the evolution kinetics, we utilize the well-known conserved spin-exchange (Kawasaki) kinetics on a two-dimensional (2) Ising system via an extensive Monte Carlo (MC) simulation study. The effect of BD is analyzed for the critical () mixtures. We observed that the dynamical scaling, exhibited by the scaled correlation function and the corresponding structure factor, changes by varying the number of disordered sites at different temperatures below the critical temperature (   ). When the system is deeply quenched at the lower BD sites, we hardly observed any significant effect on the phase separation kinetics and domain morphologies. However, in the presence of a higher BD, the evolution morphologies illustrate lamellar (anisotropic) patterns at all the temperatures studied here below   . Keywords: Ising model, Kawasaki kinetics, critical mixture, phase separation, bond-disorder. *Author for correspondence: awaneesh.phy@iitbhu.ac.in; awaneesh11@gmail.com 1. Introduction A binary () mixture stays in a homogeneous (disordered) state at high temperatures ( ≫   ) due to high entropic contribution from the thermodynamic relation  =  − . Here,  and  denote Helmholtz free energy and the internal energy of the system, respectively. The temperature and the entropy of the system are marked by  and  respectively.   implies the critical temperature at which the Ising system changes its physical behavior (e.g., order- disorder transition in the binary alloy, phase separation in the binary mixture, etc.). [1–3] When a homogeneous mixture is quenched below the critical temperature ( ≪   ), it becomes thermodynamically unstable due to small inhomogeneities initiated within the system; the phase separation in this far-from-equilibrium system begins either by the spinodal decomposition (SD) [1–5] or by the nucleation and growth (NG) [2–5] enriched in either component.