Flexoelectricity and piezoelectricity: The reason for the rich variety of phases in antiferroelectric smectic liquid crystals - art. no. 085501

The free energy of antiferroelectric smectic liquid crystals which takes in to account polar order explicitly is presented. Steric, van der Waals, piez oelectric, and flexoelectric interactions to the nearest layers, and dipola r electrostatic interactions to the nearest and to the next-nearest layers, induce indirect tilt interactions with chiral and achiral properties. whic h extend to the third- and to the fourth-nearest layers. Although the stren gth of microscopic interactions changes monotonically with decreasing tempe rature, the effective interlayer interactions change nonmonotonically and g ive rise to a nonmonotonic change of the modulation period through various phases. Increased chirality changes the phase sequence.