Field-induced phase transitions in antiferroelectric liquid crystals

A theoretical study is made of the process by which an antiferroelectric sm ectic liquid crystal undergoes a field-induced transition to ferroelectric alignment. We find that for cells of moderate thickness the initial departu re from antiferroelectric alignment occurs as a continuous Freedericksz tra nsition. The following transition from partial alignment to complete ferroe lectric ordering may occur as either a first-order or continuous transition , depending on the relative strength of some of the model parameters. The c ase where the transition is continuous provides a possible mechanism for so me recently observed thresholdless transitions in these systems. [S1063-651 X(99)01609-8].