Volume 77, Number 3, February 2007
Article Number 36004
Number of page(s) 5
Section Condensed Matter: Structural, Mechanical and Thermal Properties
Published online 01 February 2007
EPL, 77 (2007) 36004
DOI: 10.1209/0295-5075/77/36004

Modulated Hexatic- $\mth{B^\ast}$ with giant electroclinic effect rather than anticlinic Hexatic- $\mth{I_A^\ast}$ -A novel mechanism for stabilizing antiferroelectricity below Smectic- $\mth{C_A^\ast}$

R. Korlacki1, 2, A. Fukuda1, 3 and J. K. Vij1

1  Department of Electronic and Electrical Engineering, Trinity College, University of Dublin - Dublin 2, Ireland
2  Institute of Physical and Theoretical Chemistry, University of Tübingen - 72076 Tübingen, Germany
3  Department of Environmental Materials Science, Tokyo Denki University - Tokyo 101-8457, Japan

received 18 October 2006; accepted in final form 9 December 2006; published February 2007
published online 1 February 2007

The antiferroelectric hexatic phase observed below antiferroelectric ${\rm Sm}C_{A}^{*}$ has so far been considered to have the same anticlinic structure as in ${\rm Sm}C_{A}^{*}$. The orientational order parameter determined by infrared spectroscopy distinctively disproves the previous view and concludes that molecular long axes are not tilted from the ${\rm Sm}A$ layer normal. The phase can be identified as non-tilted modulated ${\rm Hx}B^{*}$ and the electric-field$\hbox{--} $induced phase transition from this phase to tilted ferroelectric ${\rm Hx}I^{*}$ can be considered as the giant electroclinic effect due to the opening of closed modulation loops.

61.30.Gd - Orientational order of liquid crystals; electric and magnetic field effects on order.
61.30.Eb - Experimental determinations of smectic, nematic, cholesteric, and other structures.
77.84.Nh - Liquids, emulsions, and suspensions; liquid crystals .

© Europhysics Letters Association 2007