EFFECTS OF ELECTRONIC CORRELATIONS ON THE THERMOELECTRIC-POWER OF THECUPRATES

We show that important anomalous features of the normal-state thermoel ectric power S of high-T-c materials can be understood as being caused by doping-dependent short-range antiferromagnetic correlations. The t heory is based on the fluctuation-exchange approximation applied to th e Hubbard model in the framework of the Kubo formalism. First, the cha racteristic maximum of S as a function of temperature can be explained by the anomalous momentum dependence of the single-particle scatterin g rate. Second, we discuss the role of the actual Fermi-surface shape for the occurrence of a sign change of S as a function of temperature and doping.