Dielectric response of ferroelectric liquid crystals in samples of finite thickness

Abstract

The structure in real planar samples of ferroelectric liquid crystals as well as the collective modes characterizing these structures, are strongly affected by surface anchoring of molecules. This is reflected in dielectric properties, which become significantly dependent on the sample thickness. The dielectric strength and the relaxation frequency of the characteristic modes (pinned Goldstone mode for the thick samples and twisted mode for the thin ones) are determined and found that for both types of structures the dielectric strength increases and the relaxation frequency decreases with increasing the sample thickness. We proved theoretically predicted thickness dependences of various physical parameters for new ferroelectric liquid crystalline compound. We concluded the experimental results are in accordance with the theory taking into account the real structure of the samples.

KEYWORDS:

• Ferroelectric liquid crystals
• dielectric response
• soft mode
• Goldstone mode

Acknowledgments

Authors are grateful to Dr. Věra Hamplová and Dr. M. Kašpar for providing 12DDL compound.

Funding

The work was supported by the Czech Science Foundation (project 18-14497S).