Large Thermoelectric Power of La2-x Sr x CuO4 Possessing Two-Dimensional Electronic Structure

In order to gain deep insight into the origin of the large thermoelectric power and metallic electrical conduction observed for La2-x Sr (x) CuO4 possessing a two-dimensional layered structure and the consequently obtained two-dimensional electronic structure, we investigate the energy-momentum dispersion and the lifetime of quasiparticles by using high-resolution angle-resolved photoemission spectroscopy. By calculating the thermoelectric power using the Bloch-Boltzmann theory and the experimentally obtained information about the electronic structure and electron scatterings, we found that the large thermoelectric power of La2-x Sr (x) CuO4 is mainly brought about by the anisotropic electron scattering caused by the strong electron correlation, and that the two-dimensional electronic structure makes almost no important contribution to the large S(T) except for rather minor effect of the van Hove singularity near the Fermi level.