Microscopic kinetics and time-dependent structure factors

Abstract

The time evolution of structure factors in the disordering process of an initially phase separated lattice depends crucially on the microscopic mechanism which drives the disordering, such as Kawasaki dynamics or vacancy mediated disordering. Monte Carlo (MC) simulations show unexpected ``dips'' in the structure factors, which mean-field theory completely fails to capture. The disordering via vacancies is slower by a surprisingly large constant factor compared to Kawasaki dynamics. A phenomenological model is introduced in order to understand the dips, and an analytical solution of Kawasaki dynamics is derived, in excellent agreement with simulations. An outline is given on how to extend the analytical solution to the more complicated case of a wandering vacancy.

4 pages, 3 figures. Replaced version with minor clarifications. Accepted by PRL