Correlation between dielectric and optical measurements in the smectic-C(*)(alpha) phase

Area of Science:

• Materials Science
• Condensed Matter Physics
• Liquid Crystal Physics

Background:

• The smectic-C(*)(alpha) (SmC(*)(alpha)) phase exhibits complex behavior influenced by the azimuthal angle difference between adjacent layers.
• Understanding the interplay between molecular structure and phase behavior is crucial for developing advanced liquid crystal materials.

Purpose of the Study:

• To investigate the optical and dielectric properties of the SmC(*)(alpha) phase in alkoxy benzoate liquid crystals.
• To correlate dielectric features with optical properties using theoretical modeling.

Main Methods:

• Optical and dielectric measurements were performed on three alkoxy benzoate homologues.
• Simulations based on the discrete phenomenological "clock model" were employed.
• Analysis focused on the azimuthal angle difference (alpha) and its temperature evolution.

Main Results:

• Two distinct dielectric behaviors were observed, dependent on the values and temperature evolution of alpha.
• For moderate alpha, the Goldstone mode dominated the SmC(*)(alpha) phase.
• For large alpha, both the soft mode (near SmA*-SmC(*)(alpha) transition) and the Goldstone mode (at lower temperatures) were identified, with discontinuities at the SmC(*)(alpha)-SmA* transition.

Conclusions:

• The azimuthal angle difference significantly dictates the dielectric response and phase behavior within the SmC(*)(alpha) phase.
• The study successfully correlated dielectric measurements with optical properties via the "clock model."
• These findings provide insights into the fundamental physics of tilted smectic liquid crystal phases.