In situ photoemission study of La1−xSrxFeO3 epitaxial thin films

We have performed in situ photoemission and O 1s X-ray absorption studies of La 1−x Sr x FeO 3 ( 0 ≤ x ≤ 0.67 ) epitaxial thin films grown by laser molecular beam epitaxy. We found that hole doping induces spectral weight transfer from below the Fermi level to above it across the gap in a highly non-rigid-band-like manner. We also observed the temperature dependence on the spectra of the x = 0.67 sample, which shows a charge disproportionation at 190 K. With decreasing temperature, we observed gradual changes of the spectra with spectral weight transfer primarily within the e g band.