PHASE-SEPARATION IN HETEROEPITAXIAL THIN-FILM GROWTH

We discuss the interplay between chemical ordering and surface roughen ing during molecular beam epitaxy. We propose microscopic and mesoscop ic descriptions of homogeneous growth where two types of atoms are dep osited, and where the interatomic potential energy leads to phase sepa ration. For deposition rates below a certain threshold value, lamellar patterns emerge in the thin film, with the concentration modulation o riented in the growth plane direction. We find that patterning of the bulk is possible by varying the temperature and the deposition rate, i n agreement with experimental results.