Short-pitch and long-pitch modes as a key for the understanding of phase sequences and types of ordering in antiferroelectric smectic liquid crystals

Abstract

A novel theoretical approach is suggested for the description of phase transitions and structures observed in antiferroelectric smectic liquid crystals. Allowance is made for two possible types of ordering: short-pitch and long-pitch helical modes. The thermodynamic behavior of the material is treated as a result of the competition between these two modes. The formulated theory reproduces the main features of the experimentally observed phase sequences and structures, thus explaining their physical nature.