IN-SITU SURFACE-ANALYSIS OF SRCUO2 HETEROEPITAXY ON SRTIO3 SUBSTRATE USING X-RAY PHOTOELECTRON-SPECTROSCOPY

An atomic scale analysis was performed for heteroepitaxial SrCuO2 film deposition on SrTiO3 substrate by laser molecular beam epitaxy. A convex shape change in Cu photoelectron intensity was observed during the initial few unit cells growth of SrCuO2 on SrTiO3(001) with TiO2 plane on the top. Angle-resolved X-ray photoelectron spectroscopy indicates that TiO2 and SrO planes are the topmost surfaces of SrTiO3 (001) substrate and growing epitaxial SrCuO2 film thicker than 1.5 nm, respectively. The switching of the topmost atomic plane from CuO(z) to SrO(y) is considered to occur in the initial growth stage of a few unit cells thickness.