Twisted Domains in Smectic B₂-Phase Under an External Electric Field

Abstract

A simplified model is used to approximate the energies of observed structures in smectic B₂- phase composed of bent-shaped molecules. Twisted, mixed (having alternating layers with twisted and uniform molecular structure) and anticlinic antiferroelectric structures coexist without an applied field having thus nearly the same energies. When an electric field is applied, mixed structure starts to be preferred. The first critical field compensates surface polar anchoring on e.g., upper sample surface and favorites partly unwound structure. The second critical field leads to transition to uniform synclinic ferroelectric structure. The behavior of the energies of B₂-phase structures under an electric field permits the estimation of model parameters, like e.g., anchoring energies.

Keywords:

• B₂-phase
• bent-shaped molecules
• field-induced structural transitions
• twisted structures

Acknowledgments

The author would like to thank Dr. M. Glogarová and Dr. V. Novotná for discussions concerning the relation of the present model to observations. This work was supported by grant No. 202/05/0431 from the Grant Agency of the Czech Republic.