title: Hard X-ray photoelectron spectroscopy of LixNi1-xO epitaxial thin films with a high lithium content.
abstract: The core-level and valence-band electronic structures of LixNi1-xO epitaxial thin films with x = 0, 0.27, and 0.48 were studied by hard X-ray photoelectron spectroscopy. A double peak structure, consisting of a main peak and a shoulder peak, and a satellite structure were observed in the Ni 2p3/2 core-level spectra. The intensity ratio of the shoulder to main peak in this double peak structure increased with increasing lithium content in LixNi1-xO. This lithium doping dependence of the Ni 2p3/2 core-level spectra was investigated using an extended cluster model, which included the Zhang-Rice (ZR) doublet bound states arising from a competition between O 2p - Ni 3d hybridization and the Ni on-site Coulomb interaction. The results indicated that the change in the intensity ratio in the main peak is because of a reduction in the ZR doublet bound states from lithium substitutions. This strongly suggests that holes compensating Li doping in LixNi1-xO are of primarily ZR character.
authors.affiliation: Synchrotron X-ray Station at SPring-8, National Institute for Materials Science (NIMS), 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan.
authors.forename: L S R
authors.initials: LS
authors.lastname: Kumara
authors.affiliation: Synchrotron X-ray Station at SPring-8, National Institute for Materials Science (NIMS), 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan.
authors.forename: Osami
authors.initials: O
authors.lastname: Sakata
authors.affiliation: Synchrotron X-ray Station at SPring-8, National Institute for Materials Science (NIMS), 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan.
authors.forename: Anli
authors.initials: A
authors.lastname: Yang
authors.affiliation: Department of Innovative and Engineered Materials, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259-J3-16, Nagatsuta, Midori, Yokohama 226-8502, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Yamauchi
authors.affiliation: Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST), Ikoma, Nara 630-0192, Japan.
authors.forename: Munetaka
authors.initials: M
authors.lastname: Taguchi
authors.affiliation: Department of Innovative and Engineered Materials, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259-J3-16, Nagatsuta, Midori, Yokohama 226-8502, Japan.
authors.forename: Akifumi
authors.initials: A
authors.lastname: Matsuda
authors.affiliation: Department of Innovative and Engineered Materials, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259-J3-16, Nagatsuta, Midori, Yokohama 226-8502, Japan.
authors.forename: Mamoru
authors.initials: M
authors.lastname: Yoshimoto