The electrohydrodynamic instability in homeotropic nematic layers

Abstract

We calculate the threshold for electrohydrodynamic convection in homeotropically oriented nematic layers with negative dielectric anisotropy that setsin after the bend-Freedericksz transition to a quasi-planar alignment has taken place. Oblique rolls are found in a larger range than in the case of planar anchoring. The most interesting prediction is that in the weakly nonlinear analysis all roll solutions are in fact unstable so that a direct transition to spatio-temporal chaos becomes possible. In the oblique-roll case this may be accompanied by a permanent local rotation of the director bend axis. Application of a planar magnetic field should stabilize the rolls