Order-Disorder Critical Behaviour in the System Oxygen on Ru(001)

  • P. Piercy
  • M. Maier
  • H. Pfnür
Conference paper
Part of the Springer Series in Surface Sciences book series (SSSUR, volume 11)

Abstract

In a LEED study of the ordering of atomic oxygen on the Ru(001) surface, the phase diagram is constructed and critical exponents are determined. Ordered oxygen phases form (2×2) structures in LEED at coverages between θ = 0.17 and saturation at θ = 0.5. A p(2×2) structure exists up to θ = 0.37. The phase diagram shows two maxima with transition temperatures to disorder of 754 K and 555 K at θ = 0.25 and 0.5, respectively. The critical exponents α,β, γ and ν for θ = 1/4, and α and β for θ = 1/2 are derived from an analysis of LEED superstructure spot intensities versus temperature and from profile analysis. They agree well with theoretically determined exponents of the 4-state Potts universality class at θ=1/4, whereas the situation is less clear at θ=1/2. Finite size effects and specific oxygen overlayer structures are discussed.

Keywords

Anisotropy Ruthenium Deconvolution Versali 

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References

  1. 1.
    See, E.G. Order in Two Dimensions, S. Sinha, ed., North Holland, New York 1980Google Scholar
  2. 2.
    L.D. Roelofs, Appl. Surf. Sci. 11/12, 425 (1982)Google Scholar
  3. 3.
    E. Domany, M. Schick, J.S. Walker, and R.B. Griffiths, Phys. Rev. B18, 2209 (1978)Google Scholar
  4. 4.
    F.Y. Wu, Rev. Mod. Phys. 54, 235 (1982)CrossRefGoogle Scholar
  5. 5.
    L.D. Roelofs, A.R. Kortan, T.L. Einstein, and R.L. Park, Phys. Rev. Lett. 46, 1465 (1981)CrossRefGoogle Scholar
  6. 6.
    T.E. Madey, H.A. Engelhardt, and D. Menzel, Surf. Sci. 48, 304 (1975)CrossRefGoogle Scholar
  7. 7.
    H. Pfnür and P. Piercy, in preparationGoogle Scholar
  8. 8.
    A.B. Anderson and M.K. Awad, Surf. Sci. 183, 289 (1987)CrossRefGoogle Scholar
  9. 9.
    M. Moritz and M.G. Lagally, Phys. Rev. Lett. 56, 865 and 2882 (1986)CrossRefGoogle Scholar
  10. 10.
    N.C. Bartelt, T.L. Einstein, and L.D. Roelofs, Phys. Rev. Lett. 56, 2881 (1986)CrossRefGoogle Scholar
  11. 11.
    M.N. Barber in: Phase Transitions, eds. C. Domb, J.L. Lebowitz, Academic Press, London 1983, Vol.8 p. 145Google Scholar
  12. 12.
    E. Umbach, Dissertation, Technische Universität München 1980 (unpublished)Google Scholar
  13. 13.
    N.C. Bartelt, T.L. Einstein, and L.D. Roelofs, Phys. Rev. B32, 2993 (1985)Google Scholar
  14. 14.
    M. Maier, Dissertation, Technische Universitüt Mlinchen 1986 (unpublished)Google Scholar
  15. 15.
    M.E. Fisher, Phys. Rev. 176, 257 (1968)CrossRefGoogle Scholar
  16. 16.
    H.E. Stanley, Introduction to Phase Transitions and Critical Phenomena, Oxford University Press, Oxford 1971Google Scholar
  17. 17.
    M.E. Fisher and R.J. Burford, Phys. Rev. 156, 583 (1967)CrossRefGoogle Scholar
  18. 18.
    D.S. Ritchie and M.E. Fisher, Phys. Rev. B5, 2668 (1972)Google Scholar
  19. 19.
    D.E. Clark, W.N. Unertl, and P.H. Kleban, Phys. Rev. B34, 4379 (1986)Google Scholar
  20. 20.
    M. Schick, Surf. Sci.125, 94 (1983)CrossRefGoogle Scholar
  21. 21.
    O.G. Mouritsen, Computer Studies of Phase Transitions and Critical Phenomena, Springer, Berlin 1984Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1988

Authors and Affiliations

  • P. Piercy
    • 1
  • M. Maier
    • 1
  • H. Pfnür
    • 1
  1. 1.Physikdepartment E20TU MünchenGarchingFed. Rep. of Germany

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