ELECTRIC-FIELD INDUCED STATIC MODULATED STRUCTURES IN NEMATICS

Linearized continuum theory is used to investigate the possible occurrence of static modulated structures (MS) under the action of an electric field (E) applied parallel to the sample planes with the initial uniform director orientation tilted with respect to the sample boundaries in a plane normal to E. Under the rigid anchoring hypothesis it is shown that the formation of MS with periodicity along E is favoured when a stabilizing magnetic field (H∥) of sufficient strength is impressed along the initial director orientation. Results are in qualitative accord with some recent experimental investigations. It appears that an instability mode having periodicity parallel to the sample planes but normal to E may set in at a threshold comparable to that of MS thus indicating a need for more detailed experimental and theoretical investigations taking proper account of the aspect ratio of the sample cell.