English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We use the discrete phenomenological model to study theoretically the phasediagrams in antiferroelectric liquid crystals (AFLCs) as a function of opticalpurity and temperature. Recent experiments have shown that in some systems thenumber of phases is reduced if the optical purity is extremely high. In somematerials the SmC$_{A}^{\star}$ phase is the only stable tilted smectic phasein the pure sample. In the scope of the presented model this high sensitivityof the phase sequence in the AFLCs to optical purity is attributed to thepiezoelectric coupling which is reduced if optical purity is reduced. We limitour study to three topologically equal phases - SmC$^{*}$, SmC$_{\alpha}^{*}$and SmC$_{A}^{*}$ and show that the reduction of optical purity forces thesystem from the antiferroelectric to the ferroelectric phase with a possibleSmC$_{\alpha}^{\star}$ between them. The effect of the flexoelectric andquadrupolar coupling is considered as well. If the phase diagram includes onlytwo phases, SmC$^{\star}$ and SmC$%_{A}^{\star}$, the flexoelectric coupling isvery small. The materials which exhibit the SmC$_{\alpha}^{\star}$ in a certainrange of optical purity and temperature, can be expected to have a significantflexoelectric coupling that is comparable with the piezoelectric coupling. Andfinally, when temperature is lowered the phase sequence SmA $\to $SmC$%_{\alpha}^{\star}$ $\to $ SmC$^{\star}$ $\to $ SmC$%_{A}^{\star}$ ispossible only in materials in which quadrupolar coupling is very strong.Comment: 17 pages including 6 figures, submitted to PR

Effect of optical purity on phase sequence in antiferroelectric liquid crystals