Specific selective reflections in the ferrielectric phases of chiral smectic liquid crystals

Theoretical investigation of selective reflections in chiral smectic liquid crystals with ferrielectric ordering is made. The structure of the phases is assumed to be produced by the coexistence and summation of short-pitch helicoidal modes with a long-pitch helix of spontaneous polarization. Small incommensurability of the short pitch helix together with the rotation of the polarization appear to cause the additional specific selective reflections. Analysis of the polarization behavior of these reflections yields that they can be easily identified experimentally. Therefore a new method of determination of the structural details of ferrielectric ordering is suggested.

Keywords:

• antiferroelectric liquid crystals
• selective reflections