Electron hole-phonon interaction, correlation of structure, and conductivity in single crystal La0.9Sr0.1FeO3-δ

The conductivity and structure of the hole-doped polaron conductor La0.9Sr0.1FeO3-delta are reported for elevated temperatures. The conductivity increases exponentially with temperature to a maximum and decreases for T>700 K following a power law, accompanied by a shift of spectral weight in the photoemission valence band. The conductivity decrease is accompanied by a phase transformation, due to the reduction of Fe, as evidenced by x-ray absorption spectra. Additional fine structures in the conductivity are correlated with a strong decrease in valence band intensity near E-F and with the onset of a corresponding structural transition.