Phase transitions of heliconical smectic-C and heliconical nematic phases in banana-shaped liquid crystals.

Matsuyama, Akihiko · Phys Rev E · 2020

basic_science · Level V

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Abstract

A mean-field theory is introduced to describe heliconical nematic (N_{TB}), heliconical smectic-C (S_{m}C_{TB}), and biaxial heliconical smectic-C (S_{m}C_{TB,b}) phases with mirror symmetry breaking. We extend our previous theories of the N_{TB} phase to the heliconical smectic-C phases, by taking into account one-dimensional spatial ordering of smectic layers. The calculated phase diagrams on the temperature-alkyl chain length plane show a rich variety of phase transitions: first- and second-order N_{TB}-S_{m}C_{TB} transitions, etc., including tricritical, tetracritical, and multicritical points. Our theory is qualitatively consistent with an experimental phase diagram.