Point Defects in Simple Ionic Solids

  • John Corish

Abstract

Apart from man’s innate need to model and the satisfaction that a good model can bring, the real purpose of scientific modelling is to increase our understanding of a system. More importantly, it provides the basis from which to move forward to understand more complex systems and to design such new systems for specific applications by making predictions about their properties. Simple ionic solids, such as the alkali and silver halides, some fluoritestructured crystals and binary oxides, provide the most accessible and well-developed testing grounds for the study, both experimental and theoretical, of point defects in crystalline materials. This is because defects in these crystals typically carry a charge different from those on the ions that comprise the normal components of the matrix. Their presence, nature, interactions and movements can therefore be rather easily quantitatively determined through the measurement of readily observed macroscopic properties such as ionic conductivity. These charges can be present whether the defects are intrinsic or extrinsic. Intrinsic defects, such as Schottky or Frenkel defects, are equilibrium thermodynamic defects and exist in all materials because the balance between the enthalpy required for their formation in a perfect lattice and the resulting increase in the entropy of the system gives rise to a minimum in the Gibbs free energy. There is a corresponding equilibrium intrinsic defect concentration at each temperature.

Keywords

Entropy Migration Enthalpy Hydroxide Bromide 

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References

  1. [1]
    F.A. Kröger and H.J. Vink, “Relations between the concentrations of imperfections in crystalline solids”, Solid State Phys., 3, 307, 1956.CrossRefGoogle Scholar
  2. [2]
    C.R.A. Catlow (ed.), “Computer Modelling in Inorganic Crystallography”, Academic Press, London, 1997.Google Scholar
  3. [3]
    N.F. Mott and M.J. Littleton, “Conduction in polar crystals. I. electrolytic conduction in solid salts”, Trans Faraday Soc., 34, 485, 1938.CrossRefGoogle Scholar
  4. [4]
    M.J. Norgett, Harwell Report AERE-R 7650, AEA Technology, Harwell, Didcot, OX11.ORA, U.K., 1974.Google Scholar
  5. [5]
    M. Leslie, SERC, Daresbury Laboratory Report DL-SCI-TM3IT, CCL, Daresbury Laboratory, Warrington, WA4, 4AD, U.K., 1982.Google Scholar
  6. [6]
    J.D. Gale, General Utility Lattice Programme, Imperial College London, U.K, 1993.Google Scholar
  7. [7]
    C.R.A. Catlow, J. Corish, P.W.M.J. Jacobs et al., “The thermodynamics of characteristic defect parameters”, J. Phys. C, 14, L121, 1981.CrossRefADSGoogle Scholar
  8. [8]
    M.J. Gillan, “The volume of formation of defects in ionic crystals”, Phil. Mag., 4, 301, 1981.Google Scholar
  9. [9]
    J.H. Harding, “Calculation of the free energy of defects in calcium fluoride”, Phys. Rev. B, 32, 6861, 1985.CrossRefADSGoogle Scholar
  10. [10]
    M. Leslie and M.J. Gillan, “The energy and elastic dipole tensor of defects in ionic crystals calculated by the supercell method”, J. Phys. C — Solid State Phys. B, 973, 1985.Google Scholar
  11. [11]
    N.L. Allan, W.C. Mackrodt, and M. Leslie, “Calculated point defect entropies in MgO”, Advances in Ceramics, 23, 257, 1989.Google Scholar
  12. [12]
    S.C. Parker and G.D. Price, “Computer modelling of phase transitions in minerals”, Adv. Solid State Chem., 1, 295, 1989.Google Scholar
  13. [13]
    G.W. Watson, T. Tschaufeser, R.A. Jackson et al., “Modelling the crystal structures of inorganic solids using lattice energy and free-energy minimisation”, In: C.R.A. Catlow (ed.), Computer Modelling in Inorganic Crystallography Academic Press, London, 1997.Google Scholar
  14. [14]
    G.W. Watson, A. Wall, and S.C. Parker, “Atomistic simulation of the effect of temperature and pressure on point defect formation in MgSiO3 perovskite and the stability of CaSiO3 perovskite”, J. Phys. Condens. Matter, 12, 8427, 2000.CrossRefADSGoogle Scholar
  15. [15]
    D.J. Harris, G.W. Watson, and S.C. Parker, “Vacancy migration at the 410/[001] symmetric tilt grain boundary of MgO: an atomistic simulation study”, Phys. Rev. B, 56, 11477, 1997.CrossRefADSGoogle Scholar
  16. [16]
    D.J. Harris, J.H. Harding, and G.W. Watson, “Computer simulation of the reactive element effect in NiO grain boundaries”, Acta Mater., 48, 3309, 2000.CrossRefGoogle Scholar
  17. [17]
    A. Devita, M.J. Gillan, J.S. Lin et al., “Defect energies in MgO treated by 1st principles methods”, Phys. Rev. B, 46, 12964, 1992.CrossRefADSGoogle Scholar
  18. [18]
    A. Devita, I. Manassidis, J.S. Lin et al., “The energetics of frenkel defects in Li2O from 1st principles”, Europhys. Letts., 19, 605, 1992.CrossRefADSGoogle Scholar
  19. [19]
    M.J. Gillan and P.W.M.J. Jacobs, “Entropy of a point defect in an ionic crystal”, Phys. Rev. B, 28, 759, 1983.CrossRefADSGoogle Scholar
  20. [20]
    B.G. Dick and A.W. Overhauser, “Theory of the dielectric constants of alkali halide crystals”, Phys. Rev., 164, 90, 1964.Google Scholar
  21. [21]
    Y.S. Kim and R.G. Gordon, “Theory of binding of inorganic crystals: application to alkali-halides and alkaline-earth-dihalide crystals”, Phys. Rev. B, 9, 3548, 1974.CrossRefADSGoogle Scholar
  22. [22]
    P.J.D. Lindan and M.J. Gillan, “Shell-model molecular dynamics simulation of superionic conduction in CaF2”, J. Phys-Cond. Matter, 5, 1019, 1993.CrossRefADSGoogle Scholar
  23. [23]
    J. Corish, “Calculated and experimental defect parameters for Silver Halides”, J. Chem. Soc., Faraday Trans., 85, 437, 1989.CrossRefGoogle Scholar
  24. [24]
    D.J. Wilson, S.A. French, and C.R.A. Catlow, “Computational studies of intrinsic defects in Silver Chloride”, Radiat. Eff. Defects Solids, 157, 857, 2002.CrossRefADSGoogle Scholar
  25. [25]
    S. Tomlinson, C.R.A. Catlow, and J.H. Harding, “Computer modelling of the defect structure of non-stoichiometric binary transition metal oxides”, J. Phys. Chem. Solids, 51, 477, 1990.CrossRefADSGoogle Scholar
  26. [26]
    C.R.A. Catlow, A.V. Chadwick, J. Corish et al., “Defect structure of doped CaF2 at high temperatures”, Phys. Rev. B, 39, 1897, 1989.CrossRefADSGoogle Scholar
  27. [27]
    J. Corish and P.W.M.J. Jacobs, “Surface and defect properties of solids”, M.W. Roberts and J.M. Thomas (eds.), Specialist Periodical Reports, vol. 2, The Chemical Society, London, p. 160, 1973.Google Scholar
  28. [28]
    J. Corish, P.W.M. Jacobs, and S. Radhakrishna, “Surface and defect properties of solids”, M.W. Roberts and J.M. Thomas (eds.), Specialist Periodical Reports, vol. 6, The Chemical Society, London, p. 219, 1977.Google Scholar

Copyright information

© Springer 2005

Authors and Affiliations

  • John Corish
    • 1
  1. 1.Department of Chemistry, Trinity CollegeUniversity of DublinIreland

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