2-DIMENSIONAL FERROELECTRIC LIQUID-CRYSTALS

The possibility of experimentally realizing two-dimensional XY critical behavior in thin ferroelectric smectic films is explored. We show that a nonferroelectric smectic-C film will exhibit XY behavior and then consider the effect of dipolar interactions and external electric field. The dipolar forces stabilize the ferromagnetic order and are relevant along the entire XY fixed line. They may, however, have little effect on the critical behavior of the present experimental systems due to their small dipole moment. We also offer some comments on the critical behavior controlled by the infinite dipolar fixed point. © 1979 The American Physical Society.