DOI: 10.1140/epje/i2002-10116-y
Controlled nucleation of point defects on a disclination line near a free surface during smectic-A-to-nematic directional melting
J. Ignés-Mullol, L. Scurtu and P. OswaldLaboratoire de Physique, Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364 Lyon, Cedex 07, France This email address is being protected from spambots. You need JavaScript enabled to view it.
(Received 1 October 2002 / Published online: 15 April 2003)
Abstract
A disclination line populated with point defects that break the
translational symmetry forms near a free nematic (N) interface in a confined
geometry. The disclination line is, however, absent in the smectic-A phase
(SmA). We use this fact to control the formation of point defect distributions
on a disclination line by directional melting of the SmA phase in a
temperature gradient. A threshold velocity (
) exists below which a
defect-free disclination line is formed. The frequency of nucleation of point
defects increases steadily for
and exhibits a remarkable
regularity. We derive an empirical scaling for
in terms of the
experimental tuning parameters. We propose a simple model that allows to
understand the formation of the point defects.
61.30.Jf - Defects in liquid crystals.
61.30.Pq - Microconfined liquid crystals: droplets, cylinders, randomly confined liquid crystals, polymer dispersed liquid crystals, and porous systems.
64.70.Md - Transitions in liquid crystals.
61.30.Hn - Surface phenomena: alignment, anchoring, anchoring transitions, surface-induced layering, surface-induced ordering, wetting, prewetting transitions, and wetting transitions.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2003
