MODULATED STRUCTURES IN TILTED CHIRAL SMECTIC FILMS

The structure of the modulated phases that can occur in systems like chiral tilted smectic films and monolayers of tilted amphiphiles is studied numerically within the mean-field approximation. Two types of modulated phases, uniaxial and hexagonal, are considered. The uniaxial phase is composed of an array of nontopological line defects and is therefore different from modulated structures occurring near ordinary commensurate-incommensurate phase transitions. The hexagonal phase displays point defects and topological pi-line defects. We discuss the energetics of these structures and the nature of the modulated-smectic-C phase transition.