Unusual defects and the electronic structure of the nonstoichiometric perovskite SrFeO_3-δ: a numerical approach

Abstract

In this article, we present a numerical attempt to model the microscopic and electronic structure of the oxygen-deficient perovskite SrFeO_3-δ in the cubic high-temperature phase. Within a classical Monte Carlo simulation, vacancies exhibit a linear Fe(III)–vac–Fe(III) configuration, an extended defect that can be described as a quadrupolaron. With reference to this defect we discuss the broad range of stability of the perovskite and the possible absence of small polaron hopping. The electronic structure is described by a simple tight-binding model, which is extended by considering the on-site spin pairing energy. Regardless of the concentration of oxygen vacancies δ, the Fermi level lies at the top of a σ* band with a strong contribution from oxygen 2p atomic orbitals. The conductivity is discussed as a function of δ considering the density of states and the degree of localization of eigenfunctions at the Fermi level.

References

1. See, e.g., C. N. R. RaoB. Raveau, Transition Metal Oxides, VCH, Weinheim, 1995; D. D. Sarma, in Metal-Insulator Transitions Revisited, ed. P. P. Edwards and C. N. R. Rao, Taylor and Francis, London, 1995; T. F. Rosenbaum, in Metal-Insulator Transitions Revisited, ed. P. P. Edwards and C. N. R. Rao, Taylor and Francis, London, 1995.
2. J.-C. Grenier, N. Ea, M. Pouchard and P. Hagenmuller, J. Solid State Chem., 1985, 58, 243.
3. M. A. Alario-Franco, J. M. Gonzales-Calbet, M. Valet-Regi and J. P. Levi, Mat. Res. Bull, 1983, 17, 733.
4. Y. Takeda, K. Kanno, T. Takada, O. Yamamoto, M. Takano, N. Nakayama and Y. Bando, J. Solid State Chem., 1986, 63, 237.
5. M. Takano, T. Okita, N. Nakayama, Y. Bando, Y. Takeda, O. Yamamoto and J. B. Goodenough, J. Solid State Chem., 1988, 73, 140.
6. J. Hombo, Y. Matsumoto and T. Kawano, J. Solid State Chem., 1990, 84, 138.
7. J. Mizusaki, M. Okayasu, S. Yamauchi and K. Fueki, J. Solid State Chem., 1992, 99, 166.
8. S. Wiβmann and K. D. Becker, Solid State Ionics, 1996, 85, 279.
9. J. B. Goodenough, J. Appl. Phys., 1962, 32, 1415.
10. S. Mathi Jaya, R. Jagadish, K. Rao and R. Asokamani, Phys. Rev. B: Condens, Matter, 1991, 43, 13274.
11. S. Matar, G. Demazeau, P. Mohn, V. Eyert and S. Najm, Eur. J. Solid State Chem., 1994, 31, 615; S. Matar, P. Mohn and G. Demazeau, J. Magn. Magn. Mater., 1995, 140–144, 169.
12. J. Hombo and K. Jinnal, Denki Kagakuoyobi Kogyo Butsuri Kagaku, 1986, 54, 686; J. Hombo and K. Nishimura, Denki Kagakuoyobi Kogyo Butsuri Kagaku, 1987, 55, 307.
13. Y. Matsumoto, J. Kurimoto and E. Sato, J. Electroanal. Chem., 1979, 102, 77; Y. Matsumoto, S. Yamada, T. Nishida and E. Sato, J. Electroanal. Chem., 1980, 127, 2360; Y. Matsumoto, K. Sugiyama and E. Sato, J. Solid State Chem., 1988, 74, 117.
14. D. E. Logan and F. Siringo, J. Phys.: Condens. Matter, 1992, 4, 3695; Th. Koslowski and D. E. Logan, J. Phys. Chem., 1994, 98, 9146; Th. Koslowski, W. Kob and K. Vollmayr, Phys. Rev. B: Condens. Matter, 1997, 56, 9469.
15. See, e.g.,M. P. AllenD. J. TildesleyComputer Simulations of Liquids, Clarendon Press, Oxford, 1987; D. Frenkel and B. Smit, Understanding Molecular Simulations, Academic Press, San Diego, CA 1996.
16. C. R. A. Catlow, in Solid State Chemistry Techniques, ed. A. K. Cheetham and P. Day, Clarendon Press, Oxford, 1987.
17. M. Martin, G. Marcus, Bin Chen and J. I. Siepmann, J. Chem. Phys., 1998, 108, 3383.
18. F. H. Stillinger and R. Lovett, J. Chem. Phys., 1968, 49, 1991.
19. Th. Koslowski and U. Beck, J. Phys.: Condens. Matter, 1999, 11, 3019.
20. W. A. Harrison, Electronic Structure and the Theory of Solids, Freeman, San Francisco, CA, 1980.
21. P. Fulde, Electron Correlations in Molecules and Solids, Springer, Berlin, 1991, p. 337.
22. H. Dücker, Th. Koslowski, W. von Niessen, M. A. Tusch and D. E. Logan, J. Non-Cryst. Solids, 1996, 207, 32; H. Dücker, W. von Niessen, Th. Koslowski, M. A. Tusch and D. E. Logan, Phys. Rev. B. Condens. Matter, 1999, 59, 871.
23. F. Gebhard, The Mott metal-insulator transition, Springer, Berlin-Heidelberg, 1997, p. 103.
24. J. Hubbard, Proc. R. Soc. London, Ser. A, 1964, 281, 401.
25. C. Lanczos, J. Res. Nat. Bur. Stand. Sect. B, 1950, 45, 225; J. K. Cullum and R. Willoughby, Lanczos algorithms for large symmetric eigenvalue problems, Birkhäuser, Boston-Basel-Stuttgart, 1985, vol. I Theory, vol. II Programs; Th. Koslowski and W. von Niessen, J. Comput. Chem., 1993, 14, 769.
26. R. S. Mulliken, J. Chem. Phys., 1955, 23, 1833.
27. P. W. Anderson, Phys. Rev., 1958, 109, 1492.
28. J. M. Ziman, J. Phys. C: Solid State Phys., 1969, 2, 1230; N. F. Mott and E. A. Davies, Electronic Processes in Non-Crystalline Materials, Oxford University Press, London, 1971.
29. Th. Koslowski and W. von Niessen, J. Phys.: Condens. Matter, 1992, 4, 6109.
30. T.-M. Chang, J. D. Bauer and J. L. Skinner, J. Chem. Phys., 1990, 93, 8973.
31. Th. Koslowski, D. G. Rowan and D. E. Logan, Ber. Bunsen-Ges. Phys. Chem., 1996, 100, 101.
32. N. F. Mott, Philos. Mag., 1972, 26, 1015.
33. N. K. Hindley, J. Non-Cryst. Solids, 1970, 5, 17; K. Niizeki, Prog. Theor. Phys., 1979, 62, 1.
34. K.-D. Becker and D. E. Mack, personal communication.
35. F. Gebhard, ref. 23, p. 89.
36. K. Schönhammer, O. Gunnarsen and R. M. Noack, Phys. Rev. B: Condens. Matter, 1995, 52, 2504.
37. G. B. Bachelet, M. Schlüter and G. A. Baraff, Phys. Rev. B: Condens. Matter, 1983, 27, 2545; G. A. Baraff and M. Schlüter, Phys. Rev. B: Condens. Matter, 1984, 30, 1853; G. A. Baraff and M. Schlüter, Phys. Rev. Lett., 1985, 55, 1327.
38. V. I. Anisimov, J. Zaanen and O. K. Andersen, Phys. Rev. B: Condens. Matter, 1991, 44, 943; P. Wei and Z. Q. Qi, Phys. Rev. B: Condens. Matter, 1994, 49, 10864.