The effect of doping electrons on the electronic structure of single-c
rystalline LaxSr1-xTiO3 samples (x = 0.001, 0.01, 0.05) has been studi
ed for the fractured surface by photoemission spectroscopy. Two peaks
in the band gap region of SrTiO3 (in-gap peaks) are induced by La subs
titution for Sr: a peak with a sharp Fermi cut-off(metallic peak) and
a broad peak centered at similar to 1.5 eV below the Fermi level (simi
lar to 1.5 eV peak). The spectral intensity of the metallic peak and t
he similar to 1.5 eV peak increase with the carrier concentration, but
the spectral width of the metallic peak does not depend upon it. The
behaviors of doping electrons on the electronic structure near the Fer
mi level of LaxSr1-xTiO3, such as no change in the spectral width of t
he metallic peak and the appearance of the similar to 1.5 eV peak, can
not be simply explained by the band theory. (C) 1997 Academic Press Li
mited.