ON THE ORIGINS OF SPONTANEOUS POLARIZATION IN TILTED SMECTIC LIQUID-CRYSTALS

The rapid electrooptic response of ferroelectric liquid crystals-strat ified (smectic) melts exhibiting spontaneous electric polarization-mak es them candidates for the next generation of electrooptic shutters an d liquid crystal displays. The model advanced here suggests that polar ity is indigenous to tilted smectics and that spontaneous polarization derives from the packing constraints mesogens experience, a tilt-depe ndent correlation of molecular conformation with orientation. First-ra nk orientational order parameters (C-xX) are nonzero with a tilt- (tem perature-) dependent magnitude, and under certain packing conditions, the sign of C-xX varies with tilt. These results have a direct bearing on experimental observations because most ferroelectric liquid crysta ls exhibit a tilt-dependent spontaneous polarization and some show an inversion of the sign of the polarization.