Author/Editor		Žekš, Boštjan; Filipič, Cene; Carlsson, Tomas
Title		Theory of ferroelectric liquid crystals
Type		članek
Source		Phys Scripta
Vol. and No.		Letnik T25
Publication year		1989
Volume		str. 362-366
Language		eng
Abstract		In the ferroelectric helicoidal smectic C* phase the chiral molecules are tilted with their long axes from normal to smectic layers. The directionof the tilt precesses as one goes from one smectic layer to another resulting in a helicoidal structure. The order parameter of the phase transition from the smectic A to the smectic C* phase is the two component tilt vector,which breaks the axial symmetry around the long molecular axis and induces the ordering of transverse molecular dipoles. The extended thermodynamic model is reviewed, which includes the bilinear as well as the biquadratic coupling between the tilt and the transverse polarization and describes in a unified way the thermodynamic properties of these systems. A microscopic model is introduced, which is consistent with the extended thermodynamic model, and the effect of the shape of moleculaes on the macroscopic properties of ferroelectric crystals is estimated.
Descriptors		BIOPHYSICS THERMODYNAMICS CRYSTALLIZATION MODELS, THEORETICAL