DEVILS STAIRCASE, CRITICAL THICKNESS, AND PROPAGATING FINGERS IN ANTIFERROELECTRIC LIQUID-CRYSTALS

From an expression for the energy of a cell containing an antiferroele ctric smectic liquid crystal with only nearest-neighbor interactions b etween layers we conclude the following: (1) a critical cell thickness exists at which the commensurability of the system changes from unity to higher values; (2) for negative dielectric anisotropy there is ano ther critical thickness below which a transition to ferroelectric alig nment cannot be homogeneously nucleated at any field; and (3) the tran sition to and from ferroelectric alignment propagates as a stable soli tary wave under certain conditions.