Advertisement

Surface anchoring and pitch variation in thin smectic C* layers in an electric field

  • V. A. Belyakov
  • E. I. Kats
Solids Structure

Abstract

The variations of the pitch of smectics C* in thin planar layers in an external electric field and their dependence on the surface anchoring are investigated theoretically. The proposed mechanism of the change in the number of half-turns of the helical structure in a finite-thickness layer upon a change in the applied field is the slip of the director on the surface of the layer through the potential barrier of surface anchoring. The equations describing the pitch variation in an external field and, in particular, the hysteresis in the jumpwise variations of the pitch for opposite directions of field variation are given and analyzed for arbitrary values of the field. For weak fields, it is found that the pitch variation in the layer is of a universal nature and is determined by only one dimensionless parameter, Sd= K22/dW, where K22 is the Frank torsion modulus, W is the surface anchoring potential, and d is the layer thickness. The possibility of direct determination of the form of the anchoring potential from the results of corresponding measurements is considered. Numerical calculations for the deviation of the director from the direction of alignment on the layer surface and pitch variations, as well as the points of pitch jumps and hysteresis in the field, are made for the Rapini model anchoring potential for values of the parameters for which the pitch variation weakly depends on the direction of the field applied in the plane perpendicular to the spiral axis of smectics C*. The changes in the pitch variation in stronger fields are discussed, and the optimal conditions for observing the discovered effects are formulated.

Keywords

Elementary Particle Potential Barrier External Field Dimensionless Parameter External Electric Field 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Proceedings of the 7th International Conference on Ferroelectric Liquid Crystals, Darmstadt University of Technology, Germany, 1999, Ferroelectrics 243–246 (2000).Google Scholar
  2. 2.
    I. Musevic, R. Blinc, and B. Zeks, The Physics of Ferroelectric and Antiferroelectric Liquid Crystals (World Scientific, Singapore, 2000).Google Scholar
  3. 3.
    P. G. de Gennes and J. Prost, The Physics of Liquid Crystals (Clarendon Press, Oxford, 1993).Google Scholar
  4. 4.
    H. Zink and V. A. Belyakov, Mol. Cryst. Liq. Cryst. 265, 445 (1995); Pis’ma Zh. Éksp. Teor. Fiz. 63, 37 (1996) [JETP Lett. 63, 43 (1996)].Google Scholar
  5. 5.
    H. Zink and V. A. Belyakov, Zh. Éksp. Teor. Fiz. 112, 524 (1997) [JETP 85, 285 (1997)]; Mol. Cryst. Liq. Cryst. 329, 457 (1999).Google Scholar
  6. 6.
    T. Furukawa, T. Yamada, K. Ishikawa, et al., Appl. Phys. B: Lasers Opt. B60, 485 (1995).Google Scholar
  7. 7.
    Z. Zhuang, Y. J. Kim, and J. S. Patel, Phys. Rev. Lett. 84, 1168 (2000).CrossRefADSGoogle Scholar
  8. 8.
    W. Greubel, Appl. Phys. Lett. 25, 5 (1974).CrossRefGoogle Scholar
  9. 9.
    G. S. Chilaya, Kristallografiya 45, 944 (2000) [Crystallogr. Rep. 45, 871 (2000)].Google Scholar
  10. 10.
    V. A. Belyakov and E. I. Kats, Zh. Éksp. Teor. Fiz. 118, 560 (2000) [JETP 91, 488 (2000)].Google Scholar
  11. 11.
    P. G. de Gennes, Solid State Commun. 6, 123 (1968).Google Scholar
  12. 12.
    R. Dreher, Appl. Phys. Lett. 12, 281 (1968).Google Scholar
  13. 13.
    V. A. Belyakov and V. E. Dmitrienko, Zh. Éksp. Teor. Fiz. 78, 1568 (1980) [Sov. Phys. JETP 51, 787 (1980)].Google Scholar
  14. 14.
    R. Dreher, Solid State Commun. 13, 1571 (1973).Google Scholar
  15. 15.
    W. J. A. Goossens, J. Phys. (Paris) 43, 1469 (1982).Google Scholar
  16. 16.
    S. A. Pikin, Structural Transformations in Liquid Crystals (Nauka, Moscow, 1981).Google Scholar
  17. 17.
    S. Chandrasekhar, Liquid Crystals (Cambridge Univ. Press, Cambridge, 1992, 2nd ed.).Google Scholar
  18. 18.
    P. O. Andreeva, V. K. Dolganov, R. Fouret, et al., Phys. Rev. E 59, 4143 (1999).CrossRefADSGoogle Scholar
  19. 19.
    L. D. Landau and E. M. Lifshitz, Course of Theoretical Physics, Vol. 8: Electrodynamics of Continuous Media (Nauka, Moscow, 1982; Pergamon, New York, 1984).Google Scholar
  20. 20.
    L. M. Blinov, E. I. Kats, and A. A. Sonin, Usp. Fiz. Nauk 152, 449 (1987) [Sov. Phys. Usp. 30, 604 (1987)].Google Scholar
  21. 21.
    L. M. Blinov and V. G. Chigrinov, Electrooptics Effects in Liquid Crystal Materials (Springer-Verlag, New York, 1994), Chap. 3.Google Scholar
  22. 22.
    V. A. Belyakov and V. E. Dmitrienko, Sov. Sci. Rev., Sect. A 13, 1 (1989).Google Scholar
  23. 23.
    V. A. Belyakov, Diffraction Optics of Complex-Structured Periodic Media (Nauka, Moscow, 1988; Springer-Verlag, New York, 1992).Google Scholar
  24. 24.
    V. A. Belyakov and V. E. Dmitrienko, in Proceedings of the Second USA-USSR Symposium on Light Scattering in Condensed Matter (Plenum, New York, 1979).Google Scholar

Copyright information

© MAIK "Nauka/Interperiodica" 2001

Authors and Affiliations

  • V. A. Belyakov
    • 1
  • E. I. Kats
    • 1
    • 2
  1. 1.Landau Institute of Theoretical PhysicsRussian Academy of SciencesChernogolovka, Moscow oblastRussia
  2. 2.Institute Laue-LangevinGrenobleFrance

Personalised recommendations