Instability of low-frequency oblique rolls in nematic liquid crystal thin films

Abstract

The transformation to the first pre-chaotic state in electrically excited nematic liquid crystal thin films is re-examined theoretically. By using multi-scale expansions and a realistic condition of the director on the three-dimensional electro-hydrodynamic equations, it is demonstrated that the uniform state of the nematic thin films transforms first to the oblique-roll pattern at frequencies below a critical value. The low-order transition line in the structure diagram is reconstructed and the associated triple point is determined, giving very good agreement with experimental observations.