Switching dynamics and surface forces in thresholdless "V-shaped" switching ferroelectric liquid crystals

Area of Science:

• Materials Science
• Condensed Matter Physics
• Electro-optics

Background:

• Smectic-C* ferroelectric liquid crystals (vFLCs) exhibit V-shaped switching, a phenomenon crucial for electro-optic applications.
• Existing electrostatic models explain low-frequency behavior but often neglect dynamical aspects and surface interactions.

Purpose of the Study:

• To develop dynamical equations based on the electrostatic model for vFLC switching.
• To predict switching speed and its amplitude dependence.
• To investigate the role of surface forces in vFLC dynamics.

Main Methods:

• Development of dynamical equations derived from the electrostatic model.
• Analysis of switching speed under varying amplitudes.
• Comparison of switching time constants between analog vFLCs and binary FLCs.
• Inclusion of surface forces into the electrostatic model.

Main Results:

• The model predicts small-amplitude switching speed and highlights strong amplitude dependence.
• A relationship between switching time constants of vFLCs and binary FLCs was established.
• Surface forces were found to be significant even with large spontaneous polarization.
• Incorporating surface forces enhanced model agreement with experimental vFLC cell dynamics.

Conclusions:

• The electrostatic model, augmented with surface forces, provides a more accurate description of vFLC dynamical response.
• Surface forces play a critical role in vFLC switching, even when electrostatic forces dominate.
• This refined model aids in understanding and optimizing vFLC device performance.