Fluctuation Modes of a Twist-Bend Nematic Liquid Crystal
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 (N_{TB}) phase. The results reveal a spectrum of overdamped fluctuations that includes two nonhydrodynamic modes and on...
| Main Authors: | , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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American Physical Society
2016-06-01
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| Series: | Physical Review X |
| Online Access: | http://doi.org/10.1103/PhysRevX.6.021041 |
| _version_ | 1818727488801472512 |
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| author | Z. Parsouzi S. M. Shamid V. Borshch P. K. Challa A. R. Baldwin M. G. Tamba C. Welch G. H. Mehl J. T. Gleeson A. Jakli O. D. Lavrentovich D. W. Allender J. V. Selinger S. Sprunt |
| author_facet | Z. Parsouzi S. M. Shamid V. Borshch P. K. Challa A. R. Baldwin M. G. Tamba C. Welch G. H. Mehl J. T. Gleeson A. Jakli O. D. Lavrentovich D. W. Allender J. V. Selinger S. Sprunt |
| author_sort | Z. Parsouzi |
| collection | DOAJ |
| description | 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 (N_{TB}) phase. The results reveal a spectrum of overdamped fluctuations that includes two nonhydrodynamic modes and one hydrodynamic mode in the N_{TB} phase, and a single nonhydrodynamic mode plus two hydrodynamic modes (the usual nematic optic axis or director fluctuations) in the higher temperature, uniaxial nematic phase. The properties of these fluctuations and the conditions for their observation are comprehensively explained by a Landau-de Gennes expansion of the free-energy density in terms of heliconical director and helical polarization fields that characterize the N_{TB} structure, with the latter serving as the primary order parameter. A “coarse-graining” approximation simplifies the theoretical analysis and enables us to demonstrate quantitative agreement between the calculated and experimentally determined temperature dependence of the mode relaxation rates. |
| first_indexed | 2024-12-17T22:14:54Z |
| format | Article |
| id | doaj.art-19bc4bc7cf854774bd75fc01e37d2d59 |
| institution | Directory Open Access Journal |
| issn | 2160-3308 |
| language | English |
| last_indexed | 2024-12-17T22:14:54Z |
| publishDate | 2016-06-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review X |
| spelling | doaj.art-19bc4bc7cf854774bd75fc01e37d2d592022-12-21T21:30:38ZengAmerican Physical SocietyPhysical Review X2160-33082016-06-016202104110.1103/PhysRevX.6.021041Fluctuation Modes of a Twist-Bend Nematic Liquid CrystalZ. ParsouziS. M. ShamidV. BorshchP. K. ChallaA. R. BaldwinM. G. TambaC. WelchG. H. MehlJ. T. GleesonA. JakliO. D. LavrentovichD. W. AllenderJ. V. SelingerS. SpruntWe 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 (N_{TB}) phase. The results reveal a spectrum of overdamped fluctuations that includes two nonhydrodynamic modes and one hydrodynamic mode in the N_{TB} phase, and a single nonhydrodynamic mode plus two hydrodynamic modes (the usual nematic optic axis or director fluctuations) in the higher temperature, uniaxial nematic phase. The properties of these fluctuations and the conditions for their observation are comprehensively explained by a Landau-de Gennes expansion of the free-energy density in terms of heliconical director and helical polarization fields that characterize the N_{TB} structure, with the latter serving as the primary order parameter. A “coarse-graining” approximation simplifies the theoretical analysis and enables us to demonstrate quantitative agreement between the calculated and experimentally determined temperature dependence of the mode relaxation rates.http://doi.org/10.1103/PhysRevX.6.021041 |
| spellingShingle | Z. Parsouzi S. M. Shamid V. Borshch P. K. Challa A. R. Baldwin M. G. Tamba C. Welch G. H. Mehl J. T. Gleeson A. Jakli O. D. Lavrentovich D. W. Allender J. V. Selinger S. Sprunt Fluctuation Modes of a Twist-Bend Nematic Liquid Crystal Physical Review X |
| title | Fluctuation Modes of a Twist-Bend Nematic Liquid Crystal |
| title_full | Fluctuation Modes of a Twist-Bend Nematic Liquid Crystal |
| title_fullStr | Fluctuation Modes of a Twist-Bend Nematic Liquid Crystal |
| title_full_unstemmed | Fluctuation Modes of a Twist-Bend Nematic Liquid Crystal |
| title_short | Fluctuation Modes of a Twist-Bend Nematic Liquid Crystal |
| title_sort | fluctuation modes of a twist bend nematic liquid crystal |
| url | http://doi.org/10.1103/PhysRevX.6.021041 |
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