Coarsening in the Ising model with vacancy dynamics

We simulate coarsening in an alloy at 50% concentration using the Ising model, under either Kawasaki (K-) or vacancy (V-) dynamics, on three different lattices (sc, fcc, bcc) at five different temperatures. At times t greater than 2000 MCS the first zero R of the spherically averaged pair correlation function obeys R˜R₀+(?t)^1/3 where R₀, ? are constants. As the temperature falls, ?_K (the value of ? for K-dynamics) falls but ?_V rises, so that at low temperatures ?_V»?_K. The ratio ?_K/?_V is approximately proportional to the equilibrium concentration of minority atoms in either phase. For the various lattices, the values of ? are roughly proportional to the diffusivities and, therefore, to the squared nearest-neighbour distances, i.e., ?_sc:?_bcc:?_fcc˜4:3:2. At T = 0.9T_c, R₀ is between 2 and 3 for both types of dynamics and all three lattices; as the temperature falls, R₀ remains near 2 for K-dynamics but falls, very roughly in proportion to the temperature, for V-dynamics.