The smectic ZA phase: Antiferroelectric smectic order as a prelude to the ferroelectric nematic

We have structurally characterized the liquid crystal (LC) phase that can appear as an intermediate state when a dielectric nematic, having polar disorder of its molecular dipoles, transitions to the almost perfectly polar-ordered ferroelectric nematic. This intermediate phase, which fills a 100-y-o...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2023-02, Vol.120 (8), p.1-e2217150120
Main Authors: Chen, Xi, Martinez, Vikina, Korblova, Eva, Freychet, Guillaume, Zhernenkov, Mikhail, Glaser, Matthew A, Wang, Cheng, Zhu, Chenhui, Radzihovsky, Leo, Maclennan, Joseph E, Walba, David M, Clark, Noel A
Format: Article
Language:English
Subjects:
antiferroelectric
Antiferroelectricity
Crystals
Dipole interactions
Ferroelectric materials
ferroelectric nematic
Ferromagnetism
Free energy
Ising model
liquid crystal
Liquid crystals
MATERIALS SCIENCE
Physical Sciences
Polarization
smectic
Taxonomy
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Summary:We have structurally characterized the liquid crystal (LC) phase that can appear as an intermediate state when a dielectric nematic, having polar disorder of its molecular dipoles, transitions to the almost perfectly polar-ordered ferroelectric nematic. This intermediate phase, which fills a 100-y-old void in the taxonomy of smectic LCs and which we term the "smectic ZA," is antiferroelectric, with the nematic director and polarization oriented parallel to smectic layer planes, and the polarization alternating in sign from layer to layer with a 180 Å period. A Landau free energy, originally derived from the Ising model of ferromagnetic ordering of spins in the presence of dipole–dipole interactions, and applied to model incommensurate antiferroelectricity in crystals, describes the key features of the nematic–SmZA–ferroelectric nematic phase sequence.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.2217150120