Temperature and Composition Dependence of Kinetics of Phase Separation in Solid Binary Mixtures

TL;DR

This study investigates how temperature and composition influence the kinetics of phase separation in solid binary mixtures using Monte Carlo simulations of the Ising model, revealing temperature-dependent growth exponents and weak curvature effects.

Contribution

It provides a detailed analysis of phase separation kinetics across different temperatures and compositions, incorporating finite-size scaling and curvature effects, which advances understanding of solid mixture behaviors.

Findings

At high temperature, domain growth follows the Lifshitz-Slyozov law with an exponent of 1/3.

At low temperature, the early-time growth exponent is smaller than 1/3.

Curvature-dependent corrections to growth are weak even in off-critical compositions.

Abstract

We present results for the kinetics of phase separation in solid binary mixtures ($A_1+A_2$) from Monte Carlo simulations of the Ising model in two dimensions. The simulation results are understood via appropriate application of the finite-size scaling theory. At moderately high temperatures, for symmetric $(50:50)$ compositions of $A_1$ and $A_2$ particles the average size of the domains exhibit power-law growth with the exponent having the Lifshitz-Slyozov value of 1/3 from very early time. However, our analysis shows that for low enough temperatures, the growth exponent at early time is smaller than the Lifshitz-Slyozov value. For composition dependence, we find that at moderate temperature, even for extreme off-critical composition, curvature dependent correction to the growth law is weak which is counterintuitive in this case that gives rise to droplet morphology. This is however consistent with the recent understanding on curvature dependence of surface tension. Results from rather general studies on the finite-size effects with the variations of temperature and composition have also been presented.