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SUMMARY:Landau Theory for ''Mendeleev's'' Tables of Polar Smectic Structur
 es - Kats\, E (Landau Institute for Theoretical Physics)
DTSTART:20130416T140000Z
DTEND:20130416T150000Z
UID:TALK44552@talks.cam.ac.uk
CONTACT:Mustapha Amrani
DESCRIPTION:Polar smectic liquid crystals exhibit a variety of phases with
  multilayer ordering. Recent progress in experimental technique and discov
 ery of several ferrielectric and antiferroelectric phases has put forward 
 a number of fundamental problems: whether the known set of structures is e
 xhaustive or other polar smectic phases exist? Is there an interconnection
  between azimuthal ordering of molecules in smectic layers and other degre
 es of freedom such as polar orientation of molecules? We employed the disc
 rete Landau model of phase transitions with two-component order parameter 
 to calculate the structures and phase diagrams of polar smectic liquid cry
 stals. Structures commensurate and incommensurate with layer spacing are f
 ormed due to frustrating next-nearest interlayer interaction. Sequences of
  phases on temperature and the dependence of the phase sequences on model 
 parameters are studied. Influence of different interlayer interactions on 
 the topology of the phase diagrams is analyzed. The calculated phase diagr
 ams enable to describe formation of various polar phases and their tempera
 ture sequences\, including the unusual reversed phase sequence and the pol
 ar phase with six-layer periodicity. Our calculations also predict the exi
 stence of a reentrant phase sequence with two incommensurate phases. The r
 esults of our calculations demonstrate that discrete Landau model of phase
  transitions can be successfully used to describe the manifold of polar sm
 ectic structures observed in experiment.\n\nCo-authors: P.V.Dolganov (Inst
 itute of Solid State Physics\, Chernogolvka\, Russia)\, V.M.Zhilin (nstitu
 te of Solid State Physics\, Chernogolvka\, Russia)\, V.K.Dolganov (nstitut
 e of Solid State Physics\, Chernogolvka\, Russia)\n\n
LOCATION:Seminar Room 1\, Newton Institute
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