Europhys. Lett.
Volume 73, Number 1, January 2006
Page(s) 28 - 34
Section Electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics
Published online 30 November 2005
Europhys. Lett., 73 (1), pp. 28-34 (2006)
DOI: 10.1209/epl/i2005-10370-1

Influence of voltage on the phase behavior of a zenithally bistable liquid-crystal device

L. Harnau and S. Dietrich

Max-Planck-Institut für Metallforschung - Heisenbergstr. 3 D-70569 Stuttgart, Germany and Institut für Theoretische und Angewandte Physik, Universität Stuttgart Pfaffenwaldring 57, D-70569 Stuttgart, Germany

received 29 June 2005; accepted in final form 9 November 2005
published online 30 November 2005

We investigate a nematic liquid crystal confined between a flat substrate with strong homeotropic anchoring and a sinusoidal surface whose local anchoring strength we vary. The numerical minimization of the total free energy demonstrates the existence of two nematic director configurations, namely the homeotropic state in which the director field is almost uniform, and the hybrid aligned nematic state, in which the director varies from homeotropic to nearly planar orientation through the cell. The calculations reveal that phase transitions between these states can be triggered by applying a voltage between the conducting substrates. Both dielectric interaction and flexoelectric polarization are taken into account, and in the numerical calculations particular attention is paid to the fact that the electric field is not constant throughout the cell.

42.70.Df - Liquid crystals.
42.79.Kr - Display devices, liquid-crystal devices.
61.30.Hn - Surface phenomena: alignment, anchoring, anchoring transitions, surface-induced layering, surface-induced ordering, wetting, prewetting transitions, and wetting transitions.

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