Advertisement

Electron correlation effects on the electronic properties of clusters

  • F. López-Urías
  • G. M. Pastor
Conference paper

Abstract

The Hubbard model is applied to icosahedral, face-centered cubic (FCC), hexagonal close-packed (HCP), and body-centered cubic (BCC) clusters having N = 13 atoms. Exact ground-state results are given as a function of the Coulomb repulsion strength U/t, number of electrons v, and total spin S. Electron correlation effects on magnetic behavior and structural changes are discussed.

PACS

36.40.Cg Electronic and magnetic properties of clusters 75.10.Lp Band and itinerant models 71.24+q Electronic structure of clusters and nanoparticles 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    I.M.L. Billas, A. Chátelain, W.A. de Beer: Science 265, 1682 (1994);ADSCrossRefGoogle Scholar
  2. S.E. Apsel, JAY. Emert, J. Deng, L.A. Bloomfield: Phys, Rev. Lett. 76, 1441 (1996) and references thereinGoogle Scholar
  3. 2.
    See, for instance, K. Lee, J. Callaway: Phys. Rev. B 48, 15358 (1993);ADSCrossRefGoogle Scholar
  4. J. Dorantes-Ddvila, H. Dreyssé, G.M. Pastor: Phys. Rev. B 46, 10432 (1992);ADSCrossRefGoogle Scholar
  5. M. Castro, D.R. Salahub: Phys. Rev. B 49, 11842 (1994);ADSCrossRefGoogle Scholar
  6. B.V. Reddy, S.N. Khanna, B.I. Dunlap: Phys. Rev. Lett. 70, 3323 (1993);ADSCrossRefGoogle Scholar
  7. J. Dorantes-Ddvila et al.: Phys. Rev. B 55, 15084 (1997)ADSCrossRefGoogle Scholar
  8. 3.
    J. Hubbard: Proc. R. Soc. London A 276, 238 (1963); A 281, 401 (1964);Google Scholar
  9. J. Kanamori: Frog. Theor, Phys. 30, 275 (1963);ADSCrossRefzbMATHGoogle Scholar
  10. M.C. Gutzwilìer: Phys. Rev. Lett. 10, 159 (1963)ADSCrossRefGoogle Scholar
  11. 4.
    L.M. Falicov, R.H. Victora: Phys. Rev. B 30, 1695 (1984);ADSCrossRefGoogle Scholar
  12. Y. Ishii, S. Sugano: J. Phys. Soc. Jon. 53, 3895 (1984);ADSCrossRefGoogle Scholar
  13. J. Callaway, D.P. Chen, R. Tang: Z. Phys. D 3, 91 (1986);ADSCrossRefGoogle Scholar
  14. J. Callaway, D.P. Chen, Phys. Rey, B 35, 3705 (1987)ADSCrossRefGoogle Scholar
  15. 5.
    G.M. Pastor, R. Hirsch, B. Xliihlschlegel: Phys. Rev. Lett. 72, 3879 (1994);ADSCrossRefGoogle Scholar
  16. G.M. Pastor, R. Hirsch, B.Xliihlschlegel: Phys, Rev. B 53, 10382 (1996)ADSCrossRefGoogle Scholar
  17. 6.
    A structure is called bipartite if two distinct subsets of lattice sites A and B can be defined such that every lattice site belongs to either A or B,and that there is no pair of NN belonging to the same subset. All NN bonds (or hoppings) Connect a site in A with a site in B Google Scholar
  18. 7.
    See, for example, S.L. Reindl, G.M. Pastor: Phys, Rev. B 47, 4680 (1993)ADSCrossRefGoogle Scholar
  19. 8.
    C. Lanczos: J. Res. Nat, Bur. Stand. 45, 255 (1950);CrossRefMathSciNetGoogle Scholar
  20. B.N. Parlett: The Symmetric Eigerivalue Problem ( Prentice-Hall, Engelwood Cliffs 1980 );Google Scholar
  21. J.K. Collum, R.A. Willoughby: Lanczos Algorithms for Large Symmetric Eigenvalue Computations (Birkhâuser, Boston 1985 ) Vol. I.Google Scholar
  22. 9.
    F. López-Urfas, G.M. Pastor: Phys. Rev, B 59, 5223 (1999)ADSCrossRefGoogle Scholar
  23. 10.
    The electron-hole transformation htia cia-leaves the Hamiltonian formally unchanged, except for an additive constant and a change of sign in the hopping integrals, which amounts to an inversion of the SP spectrumGoogle Scholar
  24. 11.
    Notice that in BCC clusters, electron-hole symmetry implies S(v) = S(2N — v), since the sign of the hopping integral t is irrelevant in bipartite structures (see [10])Google Scholar
  25. 12.
    For u = N, all spin values are degenerate at U/t = d-oo. The results for v = 13 refer then to very large but finite values of U/t, e.g., U/t = 256 as shown in Table 1Google Scholar
  26. 13.
    H.H. Lieb; Phys. Rev. Lett. 62, 1201 (1989)ADSCrossRefMathSciNetGoogle Scholar
  27. 14.
    Y. Nagaoka: Solid State Commun. 3, 409(1965);Google Scholar
  28. D.J. Thou-less: Proc. Phys. Soc. London 86, 893 (1965);ADSCrossRefMathSciNetGoogle Scholar
  29. Y. Nagaoka: Phys. Rev. 147, 392 (1966);ADSCrossRefGoogle Scholar
  30. H. Tasaki: Phys. Rev. B 40, 9192 (1989)ADSCrossRefGoogle Scholar

Copyright information

© Springer-Verlag Italia 1999

Authors and Affiliations

  • F. López-Urías
    • 1
  • G. M. Pastor
    • 1
  1. 1.Laboratoire de Physique Quantique, Unité Mixte de Recherche 5626 du CNRSUniversité Paul SabatierToulouse CedexFrance

Personalised recommendations