Cahn-Hilliard Simulation of Anisotropic Coarsening

The influence of surface tension anisotropy on the dynamics of coarsening is studied via computer simulations. The Cahn-Hilliard equation in dimension $d=2$ is modified to include an arbitrary surface tension anisotropy. For all cases studied, we find asymptotic late-stage scaling with the growth law $L \sim t^{1/3}$ unchanged. The structure factor $S({\bf k},t)$ is binned into angular wedges, and is found to exhibit scaling collapse distinct for each wedge, indicating that the asymptotic domain structure is indeed anisotropic. The Porod tail is found to be a sensitive diagnostic, allowing for quantitative measurement of the degree of anisotropy in the domain structure.