Coupling between tilt and polar orders in liquid crystal phases formed from achiral bent shaped molecules
A phenomenological description is given of the mesophases which may arise below a liquid formed from achiral molecules possessing a transverse dipole, as the result of a coupling between their tilt and polar orders. Six stable mesophases are found. Two of them have a cholesteric biaxial structure. The others display antiferroelectric or ferrielectric, incommensurately modulated, structures with in-plane or out-of-plane spontaneous polarization. The in-plane polarized structures become unstable under application of a longitudinal electric field. Other field-induced effects are discussed.
Toledano
P
Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, 05315-970, Sao Paulo, SP, Brazil and Groupe Structure des Materiaux Sous Conditions Extreinsertion markmes, SNBL /ESRF, 38043 Grenoble Cedex, France.
Martins
OG
Figueiredo Neto AM