Please use this identifier to cite or link to this item: http://dx.doi.org/10.18419/opus-5181
Authors: Longa, Lech
Fink, Werner
Trebin, Hans-Rainer
Title: Biaxiality of chiral liquid crystals
Issue Date: 1994
metadata.ubs.publikation.typ: Zeitschriftenartikel
metadata.ubs.publikation.source: Physical review, E 50 (1994), S. 3841-3852. URL http://dx.doi.org/10.1103/PhysRevE.50.3841
URI: http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-104054
http://elib.uni-stuttgart.de/handle/11682/5198
http://dx.doi.org/10.18419/opus-5181
Abstract: Using the extended de Gennes–Ginzburg–Landau free energy expansion in terms of the anisotropic part Q αβ(x) of the dielectric tensor field, a connection between the phase biaxiality and the stability of various chiral liquid crystalline phases is studied. In particular, the cholesteric phase, the cubic blue phases, and the phases characterized by an icosahedral space group symmetry are analyzed in detail. Also, a general question concerning the applicability of the mean-field approximation in describing the chiral phases is addressed. By an extensive study of the model over a wide range of the parameters, a class of phenomena, not present in the original de Gennes–Ginzburg–Landau model, has been found. These include (a) reentrant phase transitions between the cholesteric and the cubic blue phases and (b) the existence of distinct phases of the same symmetry but of different biaxialities. The phase biaxiality serves here as an extra scalar order parameter. Furthermore, it has been shown that, due to the presence of competing bulk terms in the free energy, the stable phases may acquire a large degree of biaxiality, also in liquid crystalline materials composed of effectively uniaxial molecules. A study of icosahedral space group symmetries provides a partial answer to the question of whether or not an icosahedral quasicrystalline state can be stabilized in liquid crystals. Although, in general, the stability of icosahedral structures could be enhanced by the extra terms in the free energy, no absolutely stable icosahedral phase has been found.
Appears in Collections:08 Fakultät Mathematik und Physik

Files in This Item:
File Description SizeFormat 
tre78.pdf23,99 MBAdobe PDFView/Open


Items in OPUS are protected by copyright, with all rights reserved, unless otherwise indicated.