A study of the semiconductor-metal transition in the series La1-xSrxCoO3, x=0.00.4, using electron-spectroscopy techniques is presented. The results show that the ground state of LaCoO3 has strongly mixed character. From the experiments we estimate the on-site Coulomb correlation energies Udd and Upp to be 3.4 and 6.7 eV, respectively, while the (pd) interaction strength is 2.2 eV. A comparison of the experiment with the results of a model many-body cluster calculation for the Co 2p spectra indicates a low-spin state of Co in LaCoO3. The band gap of LaCoO3 is estimated to be about 0.6 eV from ultraviolet photoemission spectroscopy and bremsstrahlung isochromat spectroscopy measurements. The semiconductor-metal transition results from overlap of doped hole states with the valence band for x0.2.
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