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Related papers: Twist-bend nematic phase from Landau-de Gennes per…

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We review the physics underlying Meyer's conjecture of how macroscopic-scale twist and bend conspire within the Frank-Oseen elasticity theory of nematics to create a heliconical arrangement of the uniaxial, apolar nematic director, the…

Soft Condensed Matter · Physics 2020-09-25 Edward T. Samulski , Alexandros G. Vanakaras , Demetri J. Photinos

In this work we start with an introductory review of the relatively recently discovered type of liquid crystals, twist-bend nematics N_{TB}. Then we describe a more detailed account of recent developments in the field. Namely: (i) Landau…

Soft Condensed Matter · Physics 2024-09-26 E. I. Kats

We report a dynamic light scattering study of the fluctuation modes in a thermotropic liquid crystalline mixture of monomer and dimer compounds that exhibits the twist-bend nematic ($\mathrm{N_{TB}}$) phase. The results reveal a spectrum of…

The twist-bend nematic (Ntb) phase is a recent addition to the nematic (N) phases of liquid crystals (LCs). A net polar order in the Ntb phase under an external electric field was predicted in several recent theoretical studies but yet to…

Soft Condensed Matter · Physics 2022-09-13 Sourav Patranabish , Aloka Sinha , Madhu B. Kanakala , Channabasaveshwar V. Yelamaggad

The twist-bend nematic phase, $N_{\rm TB}$, may be viewed as a heliconical molecular arrangement in which the director $\bf n$ precesses uniformly about an extra director field, $\bf t$. It corresponds to a nematic ground state exhibiting…

Recent experiments report that the long looked for thermotropic biaxial nematic phase has been finally detected in some thermotropic liquid crystalline systems. Inspired by these experimental observations we concentrate on some elementary…

Soft Condensed Matter · Physics 2008-09-24 David Allender , Lech Longa

Nematic twist--bend is the fifth nematic phase recognized in nature. This phase exhibits spiral orientational order, thus it is a chiral structure and it can be stabilized in systems composed of achiral molecules. The microscopic origin of…

Soft Condensed Matter · Physics 2018-11-14 Grzegorz Pająk , Lech Longa , Agnieszka Chrzanowska

The nematic twist-bend (TB) phase, exhibited by certain achiral thermotropic liquid crystalline (LC) dimers, features a nanometer-scale, heliconical rotation of the average molecular long axis (director) with equally probable left- and…

The recently discovered twist-bend nematic phase, $\rm N_{tb}$, is a non-uniform equilibrium nematic phase that presents a spontaneous bend with a precession of the nematic director, $\textbf{n}$, on a conical helix with a tilt angle…

We demonstrate that a first order isotropic-to-nematic phase transition in liquid crystals can be succesfully modeled within the generalized Landau-de Gennes theory by selecting an appropriate combination of elastic constants. The numerical…

Soft Condensed Matter · Physics 2019-02-19 Dmitry Golovaty , Young-Ki Kim , Oleg D. Lavrentovich , Michael Novack , Peter Sternberg

We present a comprehensive set of measurements of optical, dielectric, diamagnetic, elastic and viscous properties in the nematic (N) phase formed by a liquid crystalline dimer. The studied dimer, 1,7-bis-4-(4-cyanobiphenyl) heptane…

In twist-bend nematic (N\textsubscript{TB}) liquid crystals (LCs), the mean molecular orientation exhibits heliconical structure with nanoscale periodicity. On the mesoscopic scale, N\textsubscript{TB} resembles layered systems (like…

Soft Condensed Matter · Physics 2020-11-25 M. Praveen Kumar , P. Kula , Surajit Dhara

We present magneto-optic measurements on two materials that form the recently discovered twist-bend nematic (Ntb) phase. This intriguing state of matter represents a new fluid phase that is orientationally anisotropic in three directions…

Soft Condensed Matter · Physics 2015-06-22 P. K. Challa , V. Borshch , O. Parri , C. T. Imrie , S. N. Sprunt , J. T. Gleeson , O. D. Lavrentovich , A. Jakli

Certain nematic liquid crystals, e.g., those formed by banana-shaped molecules, can exhibit a low-temperature twist-bend nematic (Ntb) phase. Upon addition of chiral dopants, a chiral version of the twist-bend phase (N*tb) can be observed…

Soft Condensed Matter · Physics 2021-09-08 Natalia Kasian , Longin Lisetski , Igor Gvozdovskyy

Recently, Tavarone et al. (J. Chem. Phys. 143, 114505 (2015)) discussed phase behavior of zig-zag and bow-shaped particles composed of three needles. The authors presented very interesting results of extensive Monte Carlo simulations with…

Soft Condensed Matter · Physics 2018-04-18 Paweł Karbowniczek

The extended Frank elastic energy density is used to investigate the existence of a stable periodically modulate structure that appears as a ground state exhibiting a twist-bend molecular arrangement. For an unbounded sample, we show that…

Soft Condensed Matter · Physics 2017-06-01 M. P. Rosseto , R. R. Ribeiro de Almeida , R. S. Zola , G. Barbero , I. Lelidis , L. R. Evangelista

The nematic twist-bend ($\mathrm{N_{TB}}$) phase, exhibited by certain thermotropic liquid crystalline (LC) dimers, represents a new orientationally ordered mesophase -- the first distinct nematic variant discovered in many years. The…

In this work, we study the nematic-isotropic phase transition based on the dynamics of the Landau--De Gennes theory of liquid crystals. At the critical temperature, the Landau--De Gennes bulk potential favors the isotropic phase and nematic…

Analysis of PDEs · Mathematics 2021-07-28 Tim Laux , Yuning Liu

The chiral, heliconical (twist-bend) nematic ground state is reported in an achiral, rigid, bent-core mesogen (UD68). Similar to the nematic twist-bend (NTB) phase observed in bent molecular dimers, the NTB phase of UD68 forms macroscopic,…

The dielectric spectra of the twist bend nematic phase of the bent shaped achiral liquid crystal dimer are studied for the determination of the different relaxation modes. The two molecular processes were assigned one to the precessional…

Applied Physics · Physics 2020-01-08 K. Merkel , A. Kocot , C. Welch , G. H. Mehl
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