%0 Conference Paper
%F Oral 
%T Electric-field induced twist-bend to splay-bend nematic phase transition?
%+ Laboratoire de Physique de la Matière Condensée - UR UPJV 2081 (LPMC)
%+ Laboratoire Charles Coulomb (L2C)
%+ School of Chemistry [Southampton, UK]
%+ Laboratoire de Physique des Solides (LPS)
%A Meyer, Claire
%A Blanc, Christophe
%A Luckhurst, G.R.
%A Dozov, Ivan
%< avec comité de lecture
%B The 13th European Conference on Liquid Crystals
%C Manchester, United Kingdom
%8 2015-09-07
%D 2015
%Z Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft]Conference papers
%X 1. Introduction <BR>Spontaneously distorted nematic states have been theoretically predicted long ago for bent-shaped mesogens [1-3]. Recent experiments [4] confirmed the existence of the twist-bend nematic phase, NTB, with short-pitch heliconical precession of the director n. Another predicted state [3], the splay-bend nematic, NSB, with n oscillating in a plane, is still elusive. However, a recent birefringence study [5] suggested NSB structure of the defect wall separating two NTB domains with opposite chiralities.<BR>2. Twist-bend to splay-bend transition under strong electric field<BR>Here we investigate the NTB state of the bent-shaped dimer CB7CB under strong a.c. electric field, (E ~10 V/µm) parallel to the helix axis. This in-plane field is applied in a 2 µm cell using two ITO electrodes (Fig.1). Crossing the N- NTB transition under field, we observe in the interelectrode region slightly lower transition temperature and much stronger birefringence than that reported in the NTB phase [5], suggesting an electric-field induced NTB – NSB transition.<BR>3. Conclusion<BR>A strong electric field applied to the NTB phase induces a transition to the splay-bend nematic phase, instead to the usual uniform nematic N. We explain this in the framework of the elastic-instability model [3] of the NTB and NSB phases by taking into account the strong biaxiality of the bent-shape nematic.<BR>References<BR>[1]R. B. Meyer, in Molecular Fluids, edited by R. Balian and G. Weill (Gordon and Breach, New York 1976), pp. 273 <BR>[2]V. L. Lorman and B. Mettout, Phys. Rev. Lett. 82, 940 (1999).<BR>[3]I. Dozov, EPL (Europhysics Letters) 56, 247 (2001).<BR>[4]M. Cestari, S. Diez-Berart, D. A. Dunmur, A. Ferrarini, M. R. de la Fuente, D. J. B. Jackson, D. O. Lopez, G. R. Luckhurst, M. A. Perez-Jubindo, R. M. Richardson, J. Salud, B. A. Timimi and H. Zimmermann, Physical Review E 84, 031704 (2011).<BR>[5]C. Meyer, G. R. Luckhurst and I. Dozov, Journal of Materials Chemistry C 3, 318 (2015).
%G English
%L hal-01216758
%U https://hal.science/hal-01216758
%~ CNRS
%~ UNIV-PICARDIE
%~ UNIV-PSUD
%~ L2C
%~ UNIV-PARIS-SACLAY
%~ UNIV-PSUD-SACLAY
%~ MIPS
%~ UNIV-MONTPELLIER
%~ GS-CHIMIE
%~ GS-PHYSIQUE
%~ INSTITUT-SCIENCES-LUMIERE
%~ U-PICARDIE
%~ LPMC-UPJV
%~ LPSO
%~ UM-2015-2021