Abstract
Novel modulated textures, such as stripes and multiarmed star defects, have been observed in freely suspended films of nonchiral liquid crystals just below the smectic- to hexatic phase transition. Detailed studies using depolarized reflection microscopy suggest that the stripes are locally chiral surface splay domains of the smectic- phase, a tilted hexatic not previously identified in thermotropic liquid crystals. Line defects which form additional domain walls in the hexatic lattice lead to characteristic modulations of the basic one-dimensional stripe pattern. Inside thick circular islands, for example, stripes form circumferentially and the lines form centered 12-armed stars, resulting in a regular arrangement of hexatic domains in the form of a brick wall pattern. The observation that line defects which are not pinned at the film boundaries always form closed loops supports a model of the stripe pattern based on local chiral symmetry breaking.
- Received 4 November 1993
DOI:https://doi.org/10.1103/PhysRevE.49.3207
©1994 American Physical Society