Effects of electronic correlations on the thermoelectric power of the cuprates

We show that important anomalous features of the normal-state thermoelectric power S of high-T-c materials can be understood as being caused by doping-dependent short-range antiferromagnetic correlations. The theory is based on the fluctuation-exchange approximation applied to the Hubbard model in the framework of the Kubo formalism. First, the characteristic maximum of S as a function of temperature can be explained by the anomalous momentum dependence of the single-particle scattering 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.