Bifurcation and domain walls in thin films of liquid crystals

Abstract

A perturbation method is proposed to determine the bifurcation diagram for instabilities in thin liquid-crystalline layers which are subject to an external magnetic or electric field. Different types of continuous and discontinuous field-induced director reorientations can be classified by using elementary bifurcation theory. When two differently oriented director positions are stable, domains may appear. For weakly distorted samples the structure and velocity of walls between stable differently oriented domains is described by a solitary wavy solution of the non-linear director equation. The results of the perturbation method are applied to nematic and smectic C films.