NATURE OF THE SURFACE-INDUCED ORDER ABOVE THE DIRECT ISOTROPIC TO CHIRAL-SMECTIC-A TRANSITION

We report measurements of the electric-field-induced molecular tilt in a homogeneously aligned, single-component chiral liquid crystal that undergoes a direct isotropic-to-smectic-A transition. Above the transition to the bulk isotropic phase, there exists an in-plane molecular tilt that is linearly proportional to the applied field. It is suggested that surface order plays an essential role in realizing this in-plane molecular tilt and that its temperature dependence is much stronger than that for materials possessing the nematic-to-smectic-A transition. The effects of the phase-transition sequence and the number of constituent molecular species on the nature of the surface ordering are also discussed.