Macroscopic dynamics of the ferroelectric smectic phase with symmetry

Area of Science:

• Condensed Matter Physics
• Soft Matter Physics
• Liquid Crystal Science

Background:

• Ferroelectric smectic A liquid crystals exhibit unique properties due to their macroscopic polarization.
• Understanding the macroscopic dynamics is crucial for their application and fundamental study.

Purpose of the Study:

• To derive and present the macroscopic dynamic equations for ferroelectric smectic A liquid crystals.
• To investigate the interplay between polarization, fluid flow, and elastic phenomena.

Main Methods:

• Utilizing linear irreversible thermodynamics and symmetry arguments.
• Deriving dynamic equations valid at low frequencies and long wavelengths.

Main Results:

• Identified a static cross-coupling between layer compression and bending, resulting in elastic stresses.
• Discovered reversible cross-coupling between flow and polarization magnitude, modifying sound velocities.
• Found polarization relaxation contributes to dissipative effects for second sound.

Conclusions:

• The derived dynamic equations offer a new framework for understanding ferroelectric smectic A liquid crystals.
• Novel cross-coupling terms, previously unconsidered, are shown to influence material response.
• This work provides insights into the unique macroscopic behavior driven by the linear coupling in ferroelectric smectic A phases.