[Li, X. L.
; Lu, H. B.
; Li, Ming
; Mai, Zhenhong] Chinese Acad Sci, Inst Phys, Beijing Natl Lab Condensed Matter Phys, Beijing 100080, Peoples R China
; [Kim, Hyunjung] Sogang Univ, Dept Phys, Seoul 121742, South Korea
; [Jia, Q. J.] Chinese Acad Sci, Inst High Energy Phys, Beijing Synchrotron Radiat Fac, Beijing 100039, Peoples R China
The surfaces of epitaxial BaTiO(3) films on SrTiO(3) substrates were investigated by x-ray reflectivity (XRR) and angle-resolved x-ray photoelectron spectroscopy (ARXPS). It was shown by XRR analysis that there exists a low electron density surface layer (about 87%-93% of the electron density of the underneath BaTiO(3) layer) of 15 A on top of the film. Moreover, ARXPS results revealed a surface core-level shift of Ba in layer of about 11 A, a value which is in agreement with the thickness obtained by XRR, indicating that the surface core-level shift of Ba stems from the low electron density surface layer. (c) 2008 American Institute of Physics.