ELECTRONIC STATES IN LA2-XSRXCUO4+GAMMA PROBED BY SOFT-X-RAY ABSORPTION

[[abstract]]Oxygen K-edge absorption spectra of carefully characterized La2-xSrxCuO4+delta samples were measured using a bulk-sensitive fluorescence-yield-detection method. They reveal two distinct pre-edge peaks which evolve systematically as a function of Sr concentration. The measured spectra are quantitatively described by calculations based on the Hubbard model, including local Coulomb interactions and core-hole excitonic correlations. The absorption data are consistent with a description of electronic states based on a doped charge-transfer insulator.[[fileno]]2010117010001[[department]]物理