THEORY OF PATTERN-FORMATION IN A FREESTANDING FERROELECTRIC FILM IN AROTATING ELECTRIC-FIELD

A free-standing ferroelectric film subjected to a rotating electric in -plane field has previously been investigated under a polarizing micro scope [1]. Depending on the strength and rotation frequency of the ext ernal field, various kinds of pattern formation were observed, e.g. ri ng systems which can shrink or grow. This contribution provides a theo retical examination of the effect. It is based on the usual Landau the ory [2]. In particular, it is shown that the ring systems observed can be described as inversion walls, which exhibit soliton-like behavior( 1). The analytical results are supported by numerical simulations. As a result, a qualitative and, to some extend, also a quantitative under standing of the complex behavior of ferroelectric liquid crystals in t he case of inhomogeneously aligned smectic layers has been achieved.