Unraveling the Mystery of “Thresholdless Antiferroelectricity”: High Contrast Analog Electro‐Optics in Chiral Smectic Liquid Crystals

A liquid crystal mixture reported to exhibit “thresholdless antiferroelectricity” has been studied in experiments employing freely suspended liquid crystal films, bookshelf cell electro-optics, total internal reflection from bookshelf cell solid-liquid crystal interfaces, and computer simulation. The results show that the so-called “V-shaped” analog electro-optic response is due to the field-induced switching of a twisted smectic C* structure, stabilized by strong polar surface interactions and having the twist confined to thin surface regions by polarization space charge effects. This leaves the bulk of the cell uniform, which gives good extinction at zero field.