We have studied the electronic structure of epitaxially grown thin films of La 1-xSr xFeO 3 by in situ photoemission spectroscopy (PES) and x-ray-absorption spectroscopy (XAS) measurements. The Fe 2p and valence-band PES spectra and the O 1s XAS spectra of LaFeO 3 have been successfully reproduced by configuration-interaction cluster-model calculation and, except for the satellite structure, by band-structure calculation. From the shift of the binding energies of core levels, the chemical potential was found to be shifted downward as x was increased. Among the three peaks in the valence-band spectra of La 1-xSr xFeO 3, the peak nearest to the Fermi level (E F), due to the "e g band," was found to move toward E F and became weaker as x was increased, whereas the intensity of the peak just above E F in the O 1s XAS spectra increased with x. The gap at E F was seen for all values of x. These results indicate that changes in the spectral line shape around E F are dominated by spectral weight transfer from below to above EF across the gap and are therefore highly nonrigid-bandlike changes.
|Physical Review B - Condensed Matter and Materials Physics
|Published - 2005 1月
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