Spontaneous polarization parallel to the tilt plane in the antiferroelectric chiral smectic-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="italic">C</mml:mi></mml:mrow><mml:mrow><mml:mi mathvariant="italic">A</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>phase of liquid crystals as observed by polarized infrared spectroscopy

Miyachi, Kouichi; Matsushima, Jin; Takanishi, Yoichi; Ishikawa, Ken; Takezoe, Hideo; Fukuda, Atsuo

doi:10.1103/physreve.52.r2153

Cited by 108 publications

(56 citation statements)

References 8 publications

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“…Lower symmetry shall break the overall symmetry of the absorbance profile as shown. 13 The absorbance profiles of the bands 762 cm and 1737 cm −1 for the studied tetrapode system are exactly orthogonal to that of 1608 cm −1 band within the experimental error despite the fact that their corresponding transition dipoles are not perpendicular to the longitudinal dipole moment. This shows that macroscopically the symmetry is not lower than D 2h .…”

Section: Polarized Infrared Spectroscopymentioning

confidence: 79%

Biaxial order and a rotation of the minor director in the nematic phase of an organo-siloxane tetrapode by the electric field

Merkel

Nagaraj

Kocot

et al. 2012

The Journal of Chemical Physics

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Biaxiality in the nematic phase for a liquid crystalline tetrapode made up of organo-siloxanes mesogens is investigated using polarized infrared spectroscopy. An ordering of the minor director for the homeotropically aligned sample is found to depend on the amplitude of the in-plane electric field. On increasing the in-plane electric field, the minor director, lying initially along the rubbing direction, rotates to the direction of the applied field. The scalar order parameters of the second rank tensor are found to depend significantly on the strength of the electric field. A most significant increase is found in the nematic order parameter and in the parameter that characterizes the phase biaxiality.

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Section: Polarized Infrared Spectroscopymentioning

confidence: 79%

Biaxial order and a rotation of the minor director in the nematic phase of an organo-siloxane tetrapode by the electric field

Merkel

Nagaraj

Kocot

et al. 2012

The Journal of Chemical Physics

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“…An anticlinic achiral smectic C A phase has a double antiferroelectric polarization one in the direction z at the period d and another in the x direction, projection of the tilt in the layer plane, at the period 2d. Finally the chiral anticlinic smectic C * A phase, which is unfortunately labeled as the unique "antiferroelectric" one, is a triplicate antiferroelectric with a third surfacic polarization in the remaining y direction at the period 2d [15,47]. When applying a sufficiently high electric field in this y direction, the smectic C * A goes through a phase transition to a ferroelectric smectic C * phase with a permanent volumic polarization P in the same y direction and two antiferroelectric surface polarizations P(z) in the x and z directions with the period d.…”

Section: Appendix B Definitionsmentioning

confidence: 99%

Optical rotatory power in tilted smectic phases

Beaubois

Marcerou

Nguyen

et al. 2000

The European Physical Journal E

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Optical Rotatory Power measurements have been done on different chiral tilted smectics which lead to reproducible results. The high-temperature uniaxial SmA and SmC * α phases do not show any ORP due to the lack of in-plane anisotropy at the mesoscopic level (i.e. a few layers). At lower temperature one gets the synclinic C * and the anticlinic C * A phases with a helical precession around the layer normal which is right-handed for C * and left-handed for C * A . These phases are separated in a finite temperature range by a set of two so-called "ferrielectrics" SmC * Fi1 and SmC * Fi2 , which are not necessarily new phases, between which the handedness changes sign at a given temperature, while the change from synclinic to anticlinic tilt angle organization is spread out over the "ferrielectric" temperature range. In order to reconcile all experimental observations, otherwise apparently incompatible, it is proposed that the "ferrielectric" region is a diphasic one where the in-plane organization changes smoothly from the synclinic type to the anticlinic one.

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“…5 shows an example of the absorbance for the carbonyl group. Although the sinusoidal curve of absorbance with the minimum at ω = 0 should be obtained in conventional monomeric liquid crystals [5,6], the absorbance curve obtained in this study is not sinusoidal. Therefore, it is guessed that a domain structure having two alignments of the mesogenic parts including the carbonyl group may form both in the N and SmC A phases of the dimeric LC, which takes a bent molecular conformation.…”

Section: Resultsmentioning

confidence: 89%

“…In this study, the molecular alignment structure of both liquid-crystalline phases has been researched in detail with a polarized Fourier transform infrared spectroscopy (FT-IR). For an investigation of the molecular conformation and orientation, the polarized FT-IR can be used as a powerful tool [5,6]. The orientations of the function groups with which LC molecule forms can be…”

Section: Introductionmentioning

confidence: 99%