Stability of Antiferroelectricity and Causes for its Appearance in SmC_α ^* and SmC_A ^* Phases of a Chiral Smectic Liquid Crystal, MHPOBC

Abstract

The smectic layer thickness and the switching behavior in MHPOBC have been studied as a function of temperature; SmC α * is a tilted phase and is antiferroelectric at least in the higher-temperature region but becomes ferrielectric with decreasing temperature. The gradual appearance of ferrielectric characteristics in SmC α * suggests the emergence of the Devil's staircase. To explain the antiferroelectricity in SmC α * and SmC A * , two types of molecular interactions are proposed: one is the interaction between the spontaneous polarizations in the neighboring layers which is effective in SmC α * , and the other is the pairing of transverse dipole moments responsible for the antiferroelectricity in SmC A * .