Structures and orientational transitions in thin smectic films of tilted hexatic

We present detailed systematic studies of structural transformations in thin liquid crystal films with the transition from the smectic-C (SmC) to hexatic (HSmB) phase. For the first time, all possible structures reported in the literature are observed for one material (5O.6) with varying temperature and thickness. In unusual modulated structures, the equilibrium period of stripes is twice the domain size. We interpret these patterns in the framework of a phenomenological Landau-type theory, as equilibrium phenomena produced by a natural geometric frustration in a system having spontaneous splay distortion.