Electric-field-dependent dielectric response in the de Vries-type smectic- A* phase possessing local orientational order with nanoscale correlation length

Abstract

The dielectric strength is shown to increase and the relaxation frequency to decrease for a large temperature range up to a certain value of the electric field in the smectic-A* phase. This behavior contrasts to that observed in a conventional smectic-A*, but can be explained in terms of de Vries scenerio. On assuming the reorientation of the molecular dipoles with electric field to be of the Langevin type in the de Vries smectic-A*, we find that around 1300 molecules, corresponding to a minimum correlation length of ___45 nm in a single layer cooperatively respond to the applied field.