EFFECT OF ZN DOPING AND OXYGEN STOICHIOMETRY ON THE THERMAL-CONDUCTIVITY OF YBA2CU3O7-DELTA

The temperature dependence of the electronic contribution kappa(e) to the thermal conductivity of a two-dimensional superconductor with Van Hove singularities (VHSs) in the density of states is calculated. The influence of the position of these VHSs from the Fermi level is invest igated. Various experimental results on the thermal conductivity of YB a2(Cu1-xZnx)(3)O7-delta compounds with 0 less than or equal to x less than or equal to 0.017 and 0 less than or equal to delta less than or equal to 0.3 are analysed using the above model. A simple relation bet ween x and delta can be extracted from this analysis. This relation is shown to be correlated with the variation of the Cu(2) valence with o xygen content and Zn doping.