Electroclinic Effect Near the Smectic A C Phase Transition

3 Electroclinic Effect near the Smectic A C Phase Transition 

The electroclinic effect or the field induced tilt angle in the smectic A phase near the smectic A-C phase transition was discovered by Garoff and Meyer [19]. Later on, several authors investigated the electrooptical characteristics of the effect [20, 36, 105-106] and developed novel materials for its application [12, 107, 108]. 

The electroclinic or soft mode effect could be explained within the framework of the Landau theory of phase transitions [4]. We can write the expansion of the free energy density g of smectic A up to the 0 term as follows  

The switching time of the director tilt angle in the electroclinic effect is independent of the electric field, and is defined only by the rotational viscosity je and the elastic modulus A. The corresponding switching times are derived from the Landau-Khalatnikov equation for the balance of the viscous and elastic torques 

Let us note that when comparing A in (7.13a) and A in (7.70), we derive the following relationship  

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