Antiferroelectricity and Chiral Order in New Liquid Crystals of Nonchiral Molecules Studied by Optical Second Harmonic Generation

Macdonald, Rainer; Kentischer, F.; Warnick, Peter; Heppke, G.

doi:10.1103/physrevlett.81.4408

Cited by 108 publications

(67 citation statements)

References 11 publications

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“…Polar SmCP phases are potentially useful for NLO application because of two main reasons: (i) a high degree of polar order deriving from efficient packing, and (ii) the molecular geometry allowing for incorporation of strong chromophores with large molecular hyperpolarizabilities along the polar direction. This was realized almost as early as the discovery of polar SmCP A phases [179][180][181].…”

Section: Nonlinear Opticsmentioning

confidence: 99%

Electric‐ and Light‐Responsive Bent‐Core Liquid Crystals: From Molecular Architecture and Supramolecular Nanostructures to Applications

Zhang¹

2013

Intelligent Stimuli‐Responsive Materials

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The three classic states of matter are well known and ubiquitous in everyday life: solid, liquid, and gas. Liquid crystals (LCs), an intermediate state between solid crystal and isotropic liquid, constitute a new fascinating class of condensed soft matter uniquely combining both fluidity and long-range order. The fluid-like mobility enables LCs to be switchable under external stimuli, and crystal-like long-range order bestows anisotropic physical properties on LCs. LCs can be divided into two main classes: thermotropic and lyotropic. Thermotropic LCs consist of individual molecules (or ion pairs) and exhibit phase transitions with the change of temperature. In this case, temperature is the fundamental thermodynamic factor determining mesophase formation. Lyotropic LCs are a special type of solution system that can form mesophases as a function of both temperature and concentration of LC molecules. The building block of a lyotropic phase is an aggregate (called a micelle) formed via self-assembly of many molecules (typically on the order of 100). Examples of LCs can be found both in the natural world and in technological applications. Thermotropic LCs find 189 190 ELECTRIC-AND LIGHT-RESPONSIVE BENT-CORE LIQUID CRYSTALS a wide variety of uses in displays, and an important example of lyotropic LCs is cell membranes formed by amphiphilic lipids. Surfactants in water (i.e., soap water) constitute another useful example of lyotropic LCs. Although the majority of LCs are organic molecules, there exist many LC materials incorporating metals into organic anisotropic molecules [1-3]. These organic-inorganic hybrid LC materials are described as metallomesogens and are recently called metallotropic LCs [4] as distinguished from two main LC classes. In fact, metallomesogens can be classified as either thermotropic or lyotropic LCs depending on their composition and conditions. However, it should be noted that metallomesogens offer a material platform to incorporate magnetic, electronic, optical, redox, and catalytic properties common to inorganic materials into LCs.Although thermotropic LCs have been known to scientists for over 100 years since a discovery by the Austrian botanical physiologist Friedrich Reintizer in 1888, it was only in the late 1960s that they began to be used in display applications. Today, they are best known for their exceptionally successful commercial applications in flat panel display products such as TVs, smart phones, computer displays, and digital projectors. Although today's LC display technology is becoming very advanced, LC materials used in display devices possess the simplest nematic (N) phase and their molecules have been variants on simple rod shapes (Fig. 6.1a). Besides nematic phases, LCs can exhibit other phases: smectic (Sm), columnar (Col), and cubic phases, depending on the orientational or positional orders of their molecules. Nematic phases have only long-range orientational order, smectic mesophases exhibit one-dimensional (1D) positional order and form two-dimensional (2D) layered ...

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Section: Nonlinear Opticsmentioning

confidence: 99%

Electric‐ and Light‐Responsive Bent‐Core Liquid Crystals: From Molecular Architecture and Supramolecular Nanostructures to Applications

Zhang¹

2013

Intelligent Stimuli‐Responsive Materials

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“…Many bent-core materials with alkoxy (but not alkyl) tails show the blue crystal phase. 11,14 Melting of this crystal phase produces exclusively the macroscopically chiral 'minority' domains. The texture, essentially devoid of striped domains, may persist for many minutes, even under electric field driving.…”

Section: (C)mentioning

confidence: 99%

“…Indeed, until recently all known electrooptically active bow phases were antiferroelectric. Owing to potential applications of ferroelectric bow phases (the largest secondorder non-linear optical susceptibility observed to date for a liquid crystal was in a prototype bow-phase 17 ), and as an interesting problem in supermolecular stereocontrol, we embarked on a project aimed at the design and synthesis of a thermodynamically stable (at zero field) ferroelectric bow phase. 18 The structure of the new material, triester 3, is given in Fig.…”

Section: A Ferroelectric Bananamentioning

confidence: 99%

Supermolecular stereochemistry in ferroelectric liquid crystals

Walba

Krblova

Shao

et al. 2000

J. Phys. Org. Chem.

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“…r and θ are the polar coordinates of the relative position r 1 -r 2 . In a d-wave the orbital momentum is L=2, and the spin is in the singlet state S(S 1z ,S 2z ) [15]: (13) in the basis {D + ,D + *,D -,D -*}. These matrices generate the "image group":…”

Section: Analogy With D-wave Superconductivitymentioning

confidence: 99%

“…[7,8] that this model permits to foresee the stabilization of four ordered phases, denoted by C, R, and EL corresponding, respectively, to linear, circular and elliptic polarizations of the order-parameter wave. R describes the smectic C P phase predicted in 1992 [10] and then observed in bent-core systems [10,11], EL describes the commonly observed B2 phase [12,13], and we have proposed that C is an unmodulated approximation of the intriguing B7 phase found in 1999 [2]. In these phases the polarization and tilt waves are "parallel", in a sense explained below.…”

Section: Introductionmentioning

confidence: 99%

Dual Symmetry in Bent-Core Liquid Crystals and Unconventional Superconductors

Mettout

Lorman

2010

Symmetry

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Abstract:We extend the Landau theory of bent-core mesophases and d-wave high-T c superconductors by considering additional secondary pseudo-proper order parameters. These systems exhibit a remarkable analogy relating their symmetry groups, lists of phases, and an infinite set of physical tensors. This analogy lies upon an internal dual structure shared by the two theories. We study the dual operator transforming rotations into translations in liquid crystals, and gauge symmetries into rotations in superconductors. It is used to classify the bent-core line defects, and to analyze the electronic gap structure of lamellar d-wave superfluids.

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Antiferroelectricity and Chiral Order in New Liquid Crystals of Nonchiral Molecules Studied by Optical Second Harmonic Generation

Cited by 108 publications

References 11 publications

Electric‐ and Light‐Responsive Bent‐Core Liquid Crystals: From Molecular Architecture and Supramolecular Nanostructures to Applications

Electric‐ and Light‐Responsive Bent‐Core Liquid Crystals: From Molecular Architecture and Supramolecular Nanostructures to Applications

Supermolecular stereochemistry in ferroelectric liquid crystals

Dual Symmetry in Bent-Core Liquid Crystals and Unconventional Superconductors

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