Skip to main content

Elementary excitations, exchange interaction and spin-Peierls transition in CuGeO3

Abstract

The microscopic description of the spin-Peierls transition in pure and doped CuGeO3 is developed taking into account realistic details of crystal structure. It it shown that the presence of side-groups (here Ge) strongly influences superexchange along Cu−O−Cu path, making it antiferromagnetic. Nearest-neighbour and next-nearest neighbour exchange constantsJ nn andJ nnn are calculated. Si doping effectively segments the CuO2-chains leading toJ nn (Si)≃0 or even slightly ferromagnetic. Strong sensitivity of the exchange constants to Cu−O−Cu and (Cu−O−Cu)−Ge angles may be responsible for the spin-Peierls transition itself (“bond-bending mechanism” of the transition). The nature of excitations in the isolated and coupled spin-Peierls chains is studied and it is shown that topological excitations (solitons) play crucial role. Such soltons appear in particular in doped systems (Cu1−x Zn x GeO3, CuGe1−x Si x O3) which can explain theT SP (x) phase diagram.

This is a preview of subscription content, access via your institution.

References

  1. E. Pytte, Phys. Rev. B10, 4637 (1974).

    Article  ADS  Google Scholar 

  2. L. N. Bulaevskii, A. I. Buzdin, and D. I. Khomskii, Solid State Commun.27, 5 (1978).

    Article  ADS  Google Scholar 

  3. M. C. Cross and D. S. Fisher, Phys. Rev. B19, 402 (1979); M. C. Cross, Phys. Rev. B20, 4606 (1979).

    Article  ADS  Google Scholar 

  4. J. W. Brayet al., in “Extended Linear Chain Compounds”, ed. J. S. Miller, (Plenum, NY 1985), p. 353.

    Google Scholar 

  5. M. Hase, I. Terasaki, and K. Uchinokura, Phys. Rev. Lett.70, 3651 (1993).

    Article  ADS  Google Scholar 

  6. J. E. Leronzoet al., Phys. Rev. B50, 1278 (1994).

    Article  ADS  Google Scholar 

  7. H. Winkelmannet al, Phys. Rev. B51, 12884 (1995).

    Article  ADS  Google Scholar 

  8. B. Büchnerat al, Phys. Rev. Lett. in press.

  9. M. haseet al, Phys. Rev. Lett.71, 4059 (1993).

    Article  ADS  Google Scholar 

  10. J. P. Renardet al, Europhys. Lett.30, 475 (1995).

    Article  Google Scholar 

  11. Y. Sasagoet al, preprint cond-mat/9603185.

  12. L. P. Regnaultet al, Europhys. Lett.32, 579 (1995).

    Article  Google Scholar 

  13. W. Geertsma and D. Khomskii, Phys. Rev. B54 (1996).

  14. G. Castilla, S. Chakravarty and V. J. Emery, Phys. Rev. Lett.75, 1823 (1995).

    Article  ADS  Google Scholar 

  15. C. K. Majumdar and D. K. Ghosh, J. Math. Phys.10, 1388, 1899 (1969).

    Article  ADS  MathSciNet  Google Scholar 

  16. W. Geertsma and D. Khomskii, to be published.

  17. M. Bradenet al, preprint 1996.

  18. B. Büchner, W. Geertsma and D. Khomskii, to be published.

  19. K. Hirotaet al, Phys. Rev. Lett.31, 736 (1994).

    Article  ADS  Google Scholar 

  20. A. J. Heeger, S. Kivelson, J. R. Schrieffer, and W. P. Su, Rev. Mod. Phys.60, 781 (1988).

    Article  ADS  Google Scholar 

  21. W. P. Su, Solid State Commun.35, 899 (1980).

    Article  ADS  Google Scholar 

  22. M. Mostovoy and D. Khomskii, to be published.

  23. M. Mostovoy, M. T. Figge, and J. Knoester, to be published.

  24. The coexistence of the SP and the antiferromagnetic phases was recently treated by H. Fukuyama, T. Tanimoto and M. Saito, J. Phys. Soc. Japan,65, 1182 (1996). Our approach is rather similar, with one important difference: due to the presence of solitons the change of phase by π is allowed in our picture, whereas it is not realized in the solution obtained in the above cited paper.

    Article  ADS  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Khomskii, D., Geertsma, W. & Mostovoy, M. Elementary excitations, exchange interaction and spin-Peierls transition in CuGeO3 . Czech J Phys 46, 3239–3246 (1996). https://doi.org/10.1007/BF02548136

Download citation

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF02548136

Keywords

  • Soliton
  • Spin Chain
  • Exchange Constant
  • Elementary Excitation
  • Strong Coupling Limit