Structural Modulations in the High-Temperature Superconductor YBa2Cu3O7-δ and Semi Conducting WO3-x Aspects of Non-Equilibrium Behaviour

  • Ekhard K. H. Salje
Part of the NATO ASI Series book series (NSSB, volume 229)


A thermodynamic description of non-harmonic structural modulations may be attempted in terms of the energies required to form walls (alias kinks, boundaries, areas of large structural gradients) and the inter-wall interactions. The latter are also called ‘boundary-boundary interactions’ (BBI), and they are normally repulsive in character. The wall energies can be negative, as in equilibrium incommensurate phases, or positive if the structural state is unstable or metastable. An example for narrow walls in a matrix of a perovskitetype structure are the so-called CS planes in WO3 ( Fig.l). Different wall configurations have been described in great detail for individual chemical phases (review by Sundberg, 1981a, and Sundberg, 1981b) and it was found that these walls occur in equilibrium phases with a high degree of regularity. Here we are concerned only with walls along one of the crystallographic {10n},n>2 directions. A unifying, although more simplistic view, of the various structural and chemical features is based on the observation that the essential structural building blocks of the walls are blocks of four edge-sharing octahedra which are aligned within the walls as shown in Fig.2. These structural units represent stable configurations which are accounted for within the framework of Landau-Ginzburg theory by negative Ginzburg energies:


Oxygen Fugacity Tungsten Oxide Structural Phase Transition Wall Energy High Oxygen Fugacity 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Berglund, S., and Sahle, W., 1981, Accommodation of oxygen loss in WO3 equilibrated with CO + CO2 buffers, J. Sol. State Chem., 36:66.CrossRefGoogle Scholar
  2. Carpenter, M.A., and Salje, E., 1989, Time-dependent Landau theory for order/disorder processes in minerals, Min. Mag., 53:483.CrossRefGoogle Scholar
  3. Diehl, R., Brandt, G., and Salje, E., 1978, Crystal Structure of Triclinic WQ3,Acta Cryst., B34:1105.Google Scholar
  4. Folk, R., Iro, H., and Schwabl, I., 1979, Critical dynamics of elastic phase transitions, Phys. Rev. B20,:1229–1244.Google Scholar
  5. Harris, M.J., Salje, E., Guttler, B., and Carpenter, M.A., 1989, Structural states of natural potassium feldspar: an infrared spectroscopic study, Phys. Chem. Min. (in print).Google Scholar
  6. Iguchi, E., and Tilley, R.J.D., 1978, The elastic strain energy of crystallographic shear planes in ReO3-related oxides. 1. The formation energy of isolated CS planes, J. Sol. State Chem. 24: 121.CrossRefGoogle Scholar
  7. Iguchi, E., Salje, E., and Tilley, R.J.D., 1981, Polaron Interaction Energies in Reduced Tungsten Trioxide, J. Solid. State Chem., 38:342.CrossRefGoogle Scholar
  8. Salje, E., 1977, The structure of the orthorhombic phase of WO3, Acta Cryst., B33:574.Google Scholar
  9. Salje, E., and Guttler, B., 1984, Anderson transition and intermediate polaron formation in WO3-x: Transport properties and optical absorption, Phil. Mag., B50:607.CrossRefGoogle Scholar
  10. Salje, E., 1988, Kinetic rate laws as derived from order parameter theory I: Theoretical concepts, Phys. Chem. Min., 15:336.CrossRefGoogle Scholar
  11. Salje, E., Kuscholke, B., and Wruck, B., 1985, Domain wall formation in minerals: I Theory of twin boundary shapes in Na-feldspar, Phys. Chem. Min., 12: 132.CrossRefGoogle Scholar
  12. Salje, E., and Wruck, B., 1988, Kinetic rate laws as derived from order parameter theory II: Interpretation of experimental data by Laplace-transformation, the relaxation spectrum, and kinetic gradient coupling between two order parameters, Phys. Chem. Min., 16: 140.CrossRefGoogle Scholar
  13. Schmahl, W., Putnis, A., Salje, E., Freeman, P., Graeme-Barber, A., Jones, R., Singh, K.K., Blunt, J., Edwards, P.P., Loram, J., and Mirza, K., 1989, Twin formation and structural modulations in orthorhombic and tetragonal YBa2(Cu1-xCox)3O7, Phil. Mag. (in press).Google Scholar
  14. Sundberg, M., 1981a, Crystallographic shear in reduced tungsten trioxide, Chem. Commun. 5, University of Stockholm.Google Scholar
  15. Sundberg, M., 1981b, Structure and oxidation behaviour of W24O70, a new member of the 103 CS series of tungsten oxides, J. Solid State Chem., 35:120.CrossRefGoogle Scholar
  16. Viswanathan, K., and Salje, E., 1981, Crystal structure and charge carrier behaviour of (W12.64Mo 1.36)O41 and its significance to other related compounds, Acta Cryst., A37:449.Google Scholar

Copyright information

© Springer Science+Business Media New York 1990

Authors and Affiliations

  • Ekhard K. H. Salje
    • 1
  1. 1.IRC Superconductivity and Department of Earth SciencesCambridgeEngland

Personalised recommendations