  The electronic structure of La0.8Sr0..2MnO3/SrTiO thin film, which was
prepared by Laser MBE, was studied by X-ray photoemission spectra (XPS) in the
temperature interval of 300 to 1000 K. Experimental results showed that the
electronic state of the thin film underwent a discontinuous variation between
350 K and 450 K, indicating that the metal-semiconductor transition was
probably a discontinuous phase transition. At high temperature (450 to 1000 K),
both the binding energies of the atomic core level and valence-band of the film
shifted up with increasing the temperature, while their line-widths became
narrower, which were different from that observed at low temperature. These
phenomena are attributed to the crystal lattice expansion and related
Jahn-Teller distortion varying with temperature.
