Modulated structures of flexoelectric origin in nematic liquid crystals.
A structural instability of flexoelectric origin is predicted in a homeotropic cell, of insulating nematic liquid crystal, by the action of an electric field applied in the direction of the initially nonperturbed nematic director. The instability gives rise to a two-dimensional periodic structure. The critical field to observe the predicted modulated structure as well as the wavelength at the threshold are evaluated. Both vary as the inverse square root of the cell thickness. The role of the dielectric anisotropy on the phenomenon is investigated. Our analysis is performed in the limit of weak anchoring energy strength, where the extrapolation length is large with respect to the thickness of the nematic sample.
Barbero
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Dipartimento di Fisica del Politecnico and Instituto Nazionale della Materia, Corso Duca degli Abruzzi, Torino, Italy.
Lelidis
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