X-ray photoelectron spectroscopy (XPS) was used to analyze a commercially available (LaAlO3)0.3(Sr2TaAlO6)0.7 (001) bulk single crystal. XP spectra were obtained using incident monochromatic Al Kα radiation at 0.83401 nm. A survey spectrum together with La 3d, O 1s, C 1s, Sr 3p, Ta 4d, La 4p, Sr 3d, Al 2s, La 4d, Al 2p, Ta 5p, La 5s, Ta 4f, O 2s, Sr 4p and La 5p core level spectra and the valence band are presented. The spectra indicate the principle core level photoelectron and Auger electron signals and show only minor carbon contamination. Making use of the O 1s, Sr 3d, La 4d, Al 2p Ta 4f lines and neglecting the components related to surface contaminants, XPS quantitative analysis reveals an altered stoichiometry of the air-exposed crystal surface of La0.34Sr0.88Al0.82Ta0.43O3
