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

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: 9 November 2005

Abstract

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.