SmC_α* domains in SmC_β* phase of antiferroelectric liquid crystals

Abstract

The ferrielectricity and domain structures of the chiral smectic C_βphase (SmCC_β*) in antifer-roelectric liquid crystals were investigated. The real part of complex dielectric constant ε′ in SmC_β* shows two-step decrease with increasing DC bias field. Each decrease corresponds to the suppression of relaxational two modes: one is the ferroelectric Goldstone mode and the other is a new mode induced by DC bias field. The relaxational frequency of the latter mode is nearly the same as that of chiral smectic C_αphase (SmC_α*). Another mode was observed at the field strength where ε′ shows steeply decrease. This mode may be attributed to the boundary motion between domains or phases. Three peaks of the switching current were observed in SmC_β* and also in the lower-temperature region of SmC_α*. The peak positions are continuously linked to those of SmC_α*. It can be said that the antiferroelectric ordering of SmC_α* may appear as domains even in SmC_β* by electric bias field.

Keywords:

• antiferroelectric liquid crystal
• MHPOBC
• optical purity
• chiral smectic C_β
• chiral smectic C_α
• domain structure