Competition between ferroelectric and flexoelectric polarization in freely suspended smectic films
Institute of Physical Chemistry, University Marburg, 35032 Marburg, Germany
2 Institute of Solid State Physics, Russian Academy of Sciences, 142432 Chernogolovka, Moscow District, Russia
3 School of Chemistry, The University, Hull HU6 7RX, UK
Published online: 15 June 1999
We report a detailed ellipsometric study of freely suspended films of chiral liquid-crystal compounds possessing smectic-A and smectic-C phases. In the temperature region between the smectic-A -smectic-C bulk and surface transitions, a discontinuous reconstruction of the tilt profile across the film is observed in the presence of a constant d.c. electric field. Comparison of the measured ellipsometric quantities with values calculated from model tilt profiles reveals a competition between a structure possessing a homogeneous tilt direction and large ferroelectric polarization and a structure with opposite tilt direction in the two film halfs and large flexoelectric polarization.
PACS: 61.30.Gd – Orientational order of liquid crystals; electric and magnetic field effects on order / 64.70.Md – Transitions in liquid crystals
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999