The coarsening process in a two-dimensional hexagonal system in the region close to both spinodal and order-order transitions was investigated through the Cahn-Hilliard model. We found a distinctive region of the phase diagram where the pinning of dislocations plays only a minor role and the dynamics is led by the triple points. In this region, we found configurations of domains with the same features as those proposed by Lifshitz. As a consequence, different correlation lengths grow logarithmically in time, in good agreement with the predictions of coarsening at low temperatures proposed by Safran.

• Received 6 February 2006

DOI:https://doi.org/10.1103/PhysRevLett.97.188302