Ambidextrous bend patterns in free-standing polar smectic- CP{F} films.
We report an unusual behavior of a ferroelectric smectic-CP{F} film formed by bent-shaped molecules. The ground state of the c -director in such film is not uniform but forms a striped pattern with alternating bend deformation. We found that the sense of the alternating bend is not related to an alternating handedness defined by the mutual orientation of the tilt ( c director) and the bow ( p director) of the molecules. Despite its similarity to a previously described twist-bend instability [J. Pang and N. A. Clark, Phys. Rev. Lett. 73, 2332 (1994)], this pattern cannot be explained in terms of spontaneous chiral symmetry breaking with continuous variation of the chirality order parameter, since the synclinic order of the polar molecules predefines the chirality of the film. We discuss possible models describing the spontaneous formation of an ambidextrous bend pattern of the c director.
Eremin
Alexey
A
Otto-von-Guericke-Universität Magdeburg, IEP, Department of Nonlinear Phenomena, Universitätsplatz 2, D-39016 Magdeburg, Germany.
Nemeş
Alexandru
A
Stannarius
Ralf
R
Weissflog
Wolfgang
W