Correspondence between Smectic Layer Switching and DC Hysteresis of Apparent Tilt Angle in an Antiferroelectric Liquid Crystal Mixture

We have shown that field-induced antiferro-ferroelectric phase transition is accompanied by reversible smectic layer switching. A layer structure without any electric field applications forms a chevron structure of the same kind as in ordinary SmC*. After the application of a field, the field-induced bookshelf structure relaxes to an obtuse chevron structure. The texture change with focal conics or zigzag defects is interpreted by taking account of the field dependence of the layer tilt angle of the chevron structure. The origin of the layer switching is also discussed on the basis of the texture change.