Smectic A herringbone patterns

18th International School on Condensed Matter Physics: "Challenges of Nanoscale Science: Theory, Materials, Applications"

Kralj, S.^1,2 ; Lacaze, E.^3 ; Cordoyiannis, G.^1 ; Kutnjak, Z.^1,4

Joef Stefan Institute, Jamova 39, Ljubljana

1000, Slovenia^1

Faculty of Natural Sciences and Mathematics, University of Maribor, Koroka 160, Maribor

2000, Slovenia^2

Institut des Nano-Sciences de Paris, 4 place Jussieu, Paris

75005, France^3

Joef Stefan International Postgraduate School, Jamova 39, Ljubljana

1000, Slovenia^4

关键词: Bulk value;    Characteristic length;    Critical value;    Layer patterns;    Mesoscopics;    Nematic director;    Order parameter;    Smectic layers;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/558/1/012009/pdf
DOI  :  10.1088/1742-6596/558/1/012009

来源: IOP

【 摘 要 】

Two qualitatively different SmA structures exhibiting herringbone-type layer patterns, to which we refer as the Defectless Smectic Herringbone (DSH) and the Dislocation Decorated Smectic Herringbone (DDSH) pattern are studied by a Landau-de Gennes-Ginzburg mesoscopic approach. Liquid crystal structures are described in terms of a nematic director field and a smectic complex order parameter. It is demonstrated that, in the proximity of the N-SmA phase transition, a melting of smectic layers could be realised even for relatively weakly-tilted smectic layers in DSH patterns (i.e. θt = 100) for type I Sm4 phase. The width of melted region could be relatively large with respect to bulk values of the smectic characteristic lengths. In addition, a critical value of θtis determined at which a DDSH pattern is expected to appear.