Anticlinic structures at the surface of freely suspended smectic-Cfilms

Abstract

Ellipsometric studies have been conducted on freely suspended films of chiral smectic liquid crystals. In the temperature range of the smectic-$C$ phase, we observe sharp steplike changes of the ellipsometric quantity $\ensuremath{\Delta}$ indicating sudden inversions of the molecular tilt direction in single smectic layers near the surface. These tilt inversion transitions are strongly hysteretic with temperature differences up to 10 K between heating and cooling runs. Although the films possess two identical free surfaces, metastable states occur in which the tilt is inverted at only one surface.