Light Scattering from Incommensurate Insulators; Mainly BaMnF4

  • D. J. Lockwood
Part of the NATO ASI Series book series (NSSB, volume 166)


The light scattering work on pyroelectric BaMnF4 is reassessed here in view of new structural information on the incommensurate phase. The dispersions in the acoustic phonon velocities Vcb and Vcc are ascribed to coupling to the phason and amplitudon, respectively; the failure to observe a true soft mode in the Raman spectrum for T < Ti ≃ 247 K is attributed to the overdamped nature of the amplitudon even for T ≃ 85 K; the static central peak is associated with symmetry breaking frozen defects; and the dynamic central peak previously thought to be due to the phason is now assigned to LA-phonon — amplitudon coupling. Thus the light scattering experiments have provided no direct evidence for phasons or amplitudons. It is suggested that Brillouin scattering experiments should be performed on incommensurate ThBr4, which is a very simple system with small phason and amplitudon damping, to search for the overdamped phason and predicted amplitudon — acoustic-phonon coupling. Finally, it is demonstrated that quasiperiodic superlattices provide exciting possibilities for detailed comparisons between theory and experiment.


Central Peak Soft Mode Incommensurate Phase Rochelle Salt Transverse Acoustic 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    See the review by T. Matsubara, Jpn. J. Appl. Phys. 24, suppl. 24-2, 1 (1985).Google Scholar
  2. 2.
    J. Petzelt, Phase Transitions 2, 155 (1981).CrossRefGoogle Scholar
  3. 3.
    H. Z. Cummins and A. P. Levanyuk, eds., “Light Scattering Near Phase Transitions” (North-Holland, Amsterdam, 1983).Google Scholar
  4. 4.
    V. A. Golovko and A. P. Levanyuk, Sov.-Phys. JETP 54, 1217 (1981).Google Scholar
  5. 5.
    R. Zeyher and W. Finger, Phys. Rev. Lett. 49, 1833 (1982).ADSCrossRefGoogle Scholar
  6. 6.
    V. A. Golovko and A. P. Levanyuk in Ref. 3, Chapt. 3.Google Scholar
  7. 7.
    R. V. Pisarev, B. B. Krichevtzov, P. A. Markovin, O. Yu. Korshunov and J. F. Scott, Phys. Rev. B28, 2667 (1983).ADSGoogle Scholar
  8. 8.
    T. W. Ryan, J. Phys. C19, 1097 (1986).ADSGoogle Scholar
  9. 9.
    P. Saint-Grégoire, R. Almairac, A. Freund and J. Y. Gesland, Ferroelectrics 67, 15 (1986).CrossRefGoogle Scholar
  10. 10.
    See, for example, reviews by J. F. Scott in Rep. Prog. Phys. 12, 1055 (1979); Ferroelectrics 24, 127 (1980); in Ref. 3, Chapt. 5; and Ferroelectrics 66, 11 (1986).ADSCrossRefGoogle Scholar
  11. 11.
    D. E. Cox, S. M. Shapiro, R. A. Cowley, M. Eibschütz and H. J. Guggenheim, Phys. Rev. B19, 5754 (1979).ADSGoogle Scholar
  12. 12.
    D. E. Cox, S. M. Shapiro, R. J. Nelmes, T. W. Ryan, H. J. Bleif, R. A. Cowley, M. Eibschütz and H. J. Guggenheim, Phys. Rev. B28, 1640 (1983).ADSGoogle Scholar
  13. 13.
    M. Barthès-Régis, R. Almairac, P. St-Grégoire, C. Filippini, U. Steigenberger, J. Nouet and Y. Gesland, J. Physique Lett. 44, L829 (1983).CrossRefGoogle Scholar
  14. 14.
    P. St-Grégoire, M. Barthes, R. Almairac, J. Nouet, J. Y. Gesland, C. Fillippini and U. Steigenberger, Ferroelectrics 53, 307 (1984).CrossRefGoogle Scholar
  15. 15.
    B. B. Lavrencic and J. F. Scott, Phys. Rev. B24, 2711 (1981).ADSGoogle Scholar
  16. 16.
    V. Dvorak and J. Fousek, Phys. Stat. Sol. A61, 99 (1980).ADSCrossRefGoogle Scholar
  17. 17.
    J. F. Ryan and J. F. Scott, Solid State Commun. 14, 5 (1974) and in “Light Scattering in Solids,” M. Balkanski, R. C. C. Leite and S. P. S. Porto, eds. (Flammarion, Paris, 1976), p. 761ADSCrossRefGoogle Scholar
  18. 18.
    V. V. Eremenko, A. P. Mokhir, Yu. A. Popkov and O. L. Reznitskaya, Ukr. Fiz. Zh. 20, 146 (1975).ADSGoogle Scholar
  19. 19.
    Yu. A. Popkov, S. V. Petrov and A. P. Mokhir, Sov. J. Low Temp. Phys. 1, 91 (1975).Google Scholar
  20. 20.
    D. W. Bechtle and J. F. Scott, J. Phys. C. 10, L209 (1977).ADSCrossRefGoogle Scholar
  21. 21.
    D. W. Bechtle, J. F. Scott and D. J. Lockwood, Phys. Rev. B18, 6213 (1978).ADSGoogle Scholar
  22. 22.
    K. B. Lyons and H. J. Guggenheim, Solid State Commun. 31, 285 (1979).ADSCrossRefGoogle Scholar
  23. 23.
    A. F. Murray and D. J. Lockwood in “Proc. 7th Int. Conf. Raman Spectrosc”, W. F. Murphy, ed. (North-Holland, Amsterdam, 1980), p. 58.Google Scholar
  24. 24.
    K. B. Lyons, T. J. Negran and H. J. Guggenheim, J. Phys. C13, L415 (1980).ADSGoogle Scholar
  25. 25.
    D. J. Lockwood, A. F. Murray and N. L. Rowell, J. Phys. C14, 753 (1981).ADSGoogle Scholar
  26. 26.
    A. F. Murray, G. Brims and S. Sprunt, Solid State Commun. 39, 941 (1981).ADSCrossRefGoogle Scholar
  27. 27.
    K. B. Lyons, R. N. Bhatt, T. J. Negran and H. J. Guggenheim, Phys. Rev. B25, 1791 (1982).ADSGoogle Scholar
  28. 28.
    A. D. Bruce and R. A. Cowley, J. Phys. C11, 3609 (1978).ADSGoogle Scholar
  29. 29.
    See comments by J. F. Scott, in Ref. 3, Chapt. 5.Google Scholar
  30. 30.
    See the review by M. V. Klein, in Ref. 3, Chapt. 8.Google Scholar
  31. 31.
    A. A. Volkov, G. V. Kozlov, S. P. Lebedev, J. Petzelt and Y. Ishibashi, Ferroelectrics 45, 157 (1982).CrossRefGoogle Scholar
  32. 32.
    J. Petzelt and V. Dvorak, J. Phys. C9, 1587 (1976).ADSGoogle Scholar
  33. 33.
    I. J. Fritz, Phys. Lett. 51A, 219 (1975).ADSGoogle Scholar
  34. 34.
    See J. F. Scott, Ferroelectrics 47, 33 (1983).CrossRefGoogle Scholar
  35. 35.
    W. Taylor, D. J. Lockwood and H. Vass, Solid State Commun. 27, 547 (1978).ADSCrossRefGoogle Scholar
  36. 36.
    B. I. Halperin and C. M. Varma, Phys. Rev. B14, 4030 (1976).ADSGoogle Scholar
  37. 37.
    J. F. Scott, private communication.Google Scholar
  38. 38.
    T. W. Ryan, R. A. Cowley and S. R. Andrews, J. Phys. C19, L113 (1986).ADSGoogle Scholar
  39. 39.
    The crystals were grown from zone melted materials by H. J. Guggenheim at Bell Laboratories.Google Scholar
  40. 40.
    L. Bernard, R. Currat, P. Delamoye, C. M. E. Zeyen, S. Hubert and R. de Kouchkovsky, J. Phys. C16, 433 (1983).ADSGoogle Scholar
  41. 41.
    C. M. E. Zeyen, Physica 120B, 283 (1983).Google Scholar
  42. 42.
    S. Hubert, P. Delamoye, S. Lefrant, M. Lepostollec and M. Hussonnois, J. Solid State Chem. 36, 36 (1981).ADSCrossRefGoogle Scholar
  43. 43.
    R. Merlin, K. Bajema, R. Clarke, F.-Y. Juang and P. K. Bhattacharya, Phys. Rev. Letters 55, 1768 (1985).ADSCrossRefGoogle Scholar
  44. 44.
    See the article by R. Clarke in these Proceedings, p. 357.Google Scholar
  45. 45.
    M. W. C. Dharmawardana, D. J. Lockwood, J.-M. Baribeau and D. C. Houghton, Phys. Rev. B34, 3034 (1986).ADSGoogle Scholar

Copyright information

© Plenum Press, New York 1987

Authors and Affiliations

  • D. J. Lockwood
    • 1
  1. 1.Physics DivisionNational Research CouncilOttawaCanada

Personalised recommendations