ELECTRONIC-STRUCTURE OF P-TYPE SRTIO3 BY PHOTOEMISSION SPECTROSCOPY

The electronic structure of p-type SrTiO3 has been studied by photoemi ssion spectroscopy (PES). Comparing with the PES of n-type SrTiO3, the Fermi level of p type is lower by about 0.7 eV and a prominent featur e of Ti 3d character within the band gap, which is formed in the n-typ e SrTiO3, cannot be found in p-type SrTiO3. It is suggested that the b and structure of p-type SrTiO3 follows the rigid-band model. The reson ant photoemission study shows that the Ti 3d partial density of states in the valence band of p-type SrTiO3 is much larger than that of n-ty pe SrTiO3. Furthermore, it is also found that the satellite intensitie s of several core lines in p-type SrTiO3 are stronger than those in n- type SrTiO3. These facts suggest that the hybridization effect between the Ti 3d and O 2p states becomes stronger in p-type SrTiO3.