Collective fluctuation and switching behavior in an antiferroelectric smectic subphase appearing in the devil's staircase

We present the fluctuational and switching behaviors in an antiferroelectric phase designated as the AF phase, which appears in a temperature region above the chiral smectic Ca (SmCA*) phase of an antiferroelectric liquid crystal, (S)-4-(1-methylheptyloxy-carbonyl)phenyl. 4'-octylbiphenyl-4-carboxylate. It has been confirmed that the relaxation of the Goldstone mode due to an antiferroelectric phase mode occurs in the AF as well as the SmCA* phase. In addition, we have found that the switching behavior of the AF phase. depends on the frequency of an applied electric field. The typical tristable switching between AF and SmC* is observed under a triangular Nave of frequencies lower than 0.1Hz, though the field-induced intermediate phase appears around the frequency range corresponding to the relaxation of the Goldstone mode. We speculate the model responsible for the switching behavior of the antiferroelectric AF phase.