Showing papers by "Samo Kralj published in 2009"
TL;DR: In this paper, the main properties of liquid crystals as adequate systems in which several open questions with respect to the impact of disorder on universal phase and structural behavior could be explored are explored.
Abstract: We review the theoretical research on the influence of disorder on structure and phase behavior of condensed matter system exhibiting continuous symmetry breaking focusing on liquid crystal phase transitions. We discuss the main properties of liquid crystals as adequate systems in which several open questions with respect to the impact of disorder on universal phase and structural behavior could be explored. Main advantages of liquid crystalline materials and different experimental realizations of random field-type disorder imposed on liquid crystal phases are described.
24 citations
TL;DR: In nontreated CPG samples the layers dilate significantly with respect to the bulk liquid crystal, and the layer thickness behavior on varying temperature and R has to take into account molecular details of the liquid crystalline samples as well as memory effects.
Abstract: A detailed x-ray scattering study has been performed in the temperature range of the smectic- A phase for the liquid crystal compounds dodecylcyanobiphenyl (12CB) and octylcyanobiphenyl (8CB) confined in different controlled-pore glasses (CPGs) characterized by their average void radius R . On decreasing the temperature in bulk samples the layer thickness is increasing for 12CB and decreasing for 8CB, respectively. In nontreated CPG samples the layers dilate significantly with respect to the bulk liquid crystal. In order to explain the layer thickness behavior on varying temperature and R , one has to take into account molecular details of the liquid crystalline samples as well as memory effects.
15 citations
TL;DR: In this article, a Lebwohl-Lasher-type lattice model was used to describe the onset of orientational ordering of a system of rod-like objects.
Abstract: We studied pattern characteristics in randomly perturbed structures exhibiting continuous symmetry breaking. A Lebwohl–Lasher‐type lattice model was used which described well the onset of orientational ordering of a system of rod‐like objects. For example, such systems mimic the orientational ordering tendency in liquid crystals or in an ensemble of nanotubes. We set impurities to impose a random anisotropy type of disorder on the objects. Structural characteristics were studied as a function of concentration of impurities, interaction strength w between impurities and rod‐like objects, external ordering strength and history of samples. We showed that the characteristic linear size of patterns and range of ordering strongly depend on the history of samples for weak enough strength w. The two‐dimensional and three‐dimensional simulations yielded qualitatively similar results.
12 citations