Nematic twist–bend phase in an external field

@article{Pajak2018NematicTP,
  title={Nematic twist–bend phase in an external field},
  author={Grzegorz Pajak and Lech Longa and Agnieszka Chrzanowska},
  journal={Proceedings of the National Academy of Sciences},
  year={2018},
  volume={115},
  pages={E10303 - E10312}
}
Significance The twist–bend nematic liquid crystalline phase is the fifth nematic structure recognized in nature [Chen D, et al. (2013) Proc Natl Acad Sci USA 110:15931–15936], and its stabilization is explained by assuming a coupling between polar and nematic orderings. It exhibits macroscopically chiral heliconical orientational order on the 10-nm scale and represents a unique example of spontaneous chiral symmetry breaking for a system of achiral molecules. Understanding how an external… Expand
23 Citations

Figures and Topics from this paper

A new flexoelectric mode in twist-bend nematic liquid crystals
Abstract Mesogenic dimers in the twist-bend nematic phase exhibit much higher flexoelectric polarization than in their uniform nematic phase. In order to theoretically investigate this data, weExpand
The Beauty of Twist-Bend Nematic Phase: Fast Switching Domains, First Order Fréedericksz Transition and a Hierarchy of Structures
The twist-bend nematic phase (NTB) exhibits a complicated hierarchy of structures responsible for several intriguing properties presented here. These are: the observation of a fast electroopticExpand
Flexoelxctricity of the distorted twist bend nematic phase
Mesogenic dimers in the twist-bend nematic phase exhibit much higher flexoelectric polarization than in their uniform nematic phase. In order to theoretically investigate this data, we extend theExpand
Setting things straight in ‘The twist-bend nematic: a case of mistaken identity’
ABSTRACT Stimulated by the paper that precedes this, our aim is to correct an error made concerning the twist-bend nematic phase and to place its development, both theoretical and experimental, inExpand
Twist-bend nematic phase in the presence of molecular chirality
ABSTRACT One of the interesting questions related to bent-shaped materials is how structural chirality of the twist-bend nematic () phase can respond to the presence of molecular chirality, withExpand
Distortions in structures of the twist bend nematic phase of a bent-core liquid crystal by the electric field.
TLDR
The results agree with the predictions made from the currently proposed models for a periodically distorted N_{TB} phase of an achiral asymmetric bent-core liquid crystalline compound. Expand
Biaxiality-driven twist-bend to splay-bend nematic phase transition induced by an electric field
TLDR
It is shown by theoretical modeling that the transition from NTB to NSB nematics cannot be explained without considering explicitly the biaxiality of both phases at the microscopic scale, which strongly suggests that molecular biaXiality should be a key factor favoring the stability of the NSB phase. Expand
Dielectric response of electric-field distortions of the twist-bend nematic phase for LC dimers.
TLDR
Wide band dielectric spectroscopy of bent-shaped achiral liquid-crystal dimers 1″-n″-bis(4-cyanobiphenyl-4'-yl) n-alkanes has been investigated in a frequency range 0.1 Hz-100 MHz using planar-aligned cells of sample thicknesses over a temperature range that covers both nematic and twist bend nematic phases. Expand
Helicoidal dynamics of biaxial curved rods in twist-bend nematic phases unveiled by unsupervised machine learning techniques.
TLDR
A machine learning protocol is devised to characterize the helicoidal particle trajectories, finding that their pitch and radius are determined by the pitch and conical angle of the N_{TB} phase thereby connecting its structural and dynamical properties. Expand
Soft modes of the dielectric response in the twist-bend nematic phase and identification of the transition to a nematic splay bend phase in the CBC7CB dimer.
TLDR
The frequency drop of the mode on increasing the bias field is interpreted as unwinding of a helix and an indication of the formation of a field induced nematic splay bend phase (NSB), and this finding is also confirmed by birefringence data in the presence of strong bias fields. Expand
...
1
2
3
...

References

SHOWING 1-10 OF 134 REFERENCES
A continuum description for cholesteric and nematic twist-bend phases based on symmetry considerations
ABSTRACT The recently discovered twist-bend nematic phase, Ntb, is a non-uniform equilibrium nematic phase that presents a spontaneous bend with a precession of the nematic director, n, on a conicalExpand
Molecular geometry, twist-bend nematic phase and unconventional elasticity: a generalised Maier-Saupe theory.
TLDR
Here, using a major extension of the Maier-Saupe molecular field theory, the transition from the nematic (N) to the NTB phase is described, and it is shown that on approaching the transition there is a gradual softening of the bend mode in the N phase. Expand
Nematic twist-bend phase with nanoscale modulation of molecular orientation
TLDR
This work experimentally demonstrates a new nematic order, formed by achiral molecules, in which the director follows an oblique helicoid, maintaining a constant oblique angle with the helix axis and experiencing twist and bend. Expand
Nematic twist-bend phase under external constraints
ABSTRACT The recently discovered twist-bend nematic phase, NTB, has short-pitched heliconical structure with doubly degenerate handedness. In contrast to the classic nematic, in the NTB phase theExpand
A molecular theory of nematic-nematic phase transitions in mesogenic dimers.
TLDR
A simple molecular model that mimics the key features and symmetry (C2V) of this class of mesogens is presented and key experimental results on the NX phase of liquid crystalline dimers are discussed in the light of the theoretical predictions, which are also contrasted with the predictions of the twist-bend nematic model. Expand
On the twist-bend nematic phase formed directly from the isotropic phase
Abstract The intriguing twist-bend nematic (NTB) phase is formed, primarily, by liquid crystal dimers having odd spacers. Typically, the phase is preceded by a nematic (N) phase via a weakExpand
The twist-bend nematic phase: molecular insights from a generalised Maier–Saupe theory
ABSTRACT Bent-shaped liquid crystal dimers exhibit a non-conventional nematic phase, which in the last few years has been actively investigated. A structural model of this phase has been proposed,Expand
Twist-bend nematic phases of bent-shaped biaxial molecules.
TLDR
It is shown that by controlling the biaxiality of the molecule's arms, up to four ordered phases can become stable and a V-shaped molecule shows a stronger ability to form stable NTB than a biaXial nematic phase. Expand
Electric field distortions in structures of the twist bend nematic (NTB) phase of a bent-core liquid crystal
Dielectric spectroscopy of a twist–bend nematic phase (NTB) of an achiral bent–core liquid crystalline compound under DC bias is used to investigate its response to electric field. Two collectiveExpand
Twist-bend heliconical chiral nematic liquid crystal phase of an achiral rigid bent-core mesogen.
  • D. Chen, M. Nakata, +8 authors N. Clark
  • Materials Science, Physics
  • Physical review. E, Statistical, nonlinear, and soft matter physics
  • 2014
TLDR
The chiral, heliconical (twist-bend) nematic ground state is reported in an achiral, rigid, bent-core mesogen (UD68) and exhibits nanoscale, periodic modulation with no associated modulation of the electron density. Expand
...
1
2
3
4
5
...