Effect of La Doping on the Electronic Structure of SrTiO₃

Abstract

For undoped-SrTiO₃ and La-doped SrTiO₃ single crystals, X-ray photoemission spectroscopy (XPS) measurements were performed with monochromated Al Kα radiation, Valence band (VB) spectra of as-fractured SrTiO₃ exhibit two peaks, P1 and P2, arising from the O 2pπ and O 2pσ bonding orbitals, respectively. Upon adding 3.0atm% of La to SrTiO₃, the valley between P1 and P2 disappears in the VB spectrum. Calculated VB spectra obtained from a molecular orbital calculation reproduce well the experimental XPS spectra for the samples.