Structural transitions of smectic phases formed by achiral bent-core molecules

Tilted smectic phases of achiral banana-shaped molecules are polar and may form a number of different states (chiral or racemic, antiferroelectric or ferroelectric), which can be interchanged by external fields. in thin films they may assume various layer structures (vertical, tilted or horizontally modulated), which can be set by external effects. In this paper we describ e electric field and mechanical shear induced structural transitions in sme ctic phases of bent-cole molecules. We discuss the field-induced distortion of the antiferroelectric state and the changeover of the chirality.