Theory of ordering dynamics forCu3Au

Abstract

A coarse-grained model for a ${\mathrm{Cu}}_3$Au system undergoing an order-disorder transition is constructed. The model is characterized by a Ginzburg-Landau Hamiltonian with a three-component order parameter and the symmetry of the ${\mathrm{Cu}}_3$Au system. The ordering dynamics of this model subjected to a temperature quench are then studied by use of Langevin dynamics. The model is analyzed with a generalization of the recently developed first-principles theory of unstable thermodynamic systems. The theoretical results are in agreement with the observed features in recent growth-kinetic experiments on ${\mathrm{Cu}}_3$Au.