%0 Journal Article
%T Optical and confocal microscopy observations of screw dislocations in smectic-A liquid crystals
%+ Laboratoire de Physique de la Matière Condensée - UR UPJV 2081 (LPMC)
%+ Laboratoire des colloïdes, verres et nanomatériaux (LCVN)
%+ Laboratoire de Physique des Solides (LPS)
%A Lelidis, Ioannis
%A Blanc, Christophe
%A Kléman, M.
%< avec comité de lecture
%@ 1539-3755
%J Physical Review E : Statistical, Nonlinear, and Soft Matter Physics
%I American Physical Society
%V 74
%N 5
%P 051710
%8 2006-11-27
%D 2006
%R 10.1103/PhysRevE.74.051710
%K defects
%K dislocations
%K plasticity
%K smectics
%K liquid crystals
%Z 61.30.Jf, 61.72.Ff, 61.72.Lk, 62.20.Fe
%Z Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft]Journal articles
%X We present experimental evidence of the presence of isolated screw dislocations in smectic-A liquid crystals observed by polarizing microscopy. In a wedge-shaped homeotropic cell, the edge and screw dislocations interaction gives rise to a strong-enough optical contrast and makes visible their mutual intersections at temperatures close to the smectic-A to smectic-C phase transition temperature. The nature of the defects is confirmed by confocal microscopy observations. At large scale we observe a forest of screw dislocations, perpendicular to the smectic layers, across the thickness of the cell (end-on configuration). Their density varies between 109 and 1012m−2. In situ observations of dislocations under stress, in the optical microscope, provide quantitative information about the screw-edge dislocation interactions. The latter interaction is calculated in the unharmonic approximation and it gives rise to an observed yield stress.
%G English
%L hal-01208105
%U https://hal.science/hal-01208105
%~ CNRS
%~ UNIV-PICARDIE
%~ UNIV-MONTP2
%~ UNIV-PSUD
%~ LCVN
%~ UNIV-PARIS-SACLAY
%~ UNIV-PSUD-SACLAY
%~ UNIV-MONTPELLIER
%~ GS-PHYSIQUE
%~ U-PICARDIE
%~ LPMC-UPJV
%~ LPSO
%~ UM1-UM2