title: Metal-induced gap states at well defined alkali-halide/metal interfaces.
abstract: In order to search for states specific to insulator/metal interfaces, we have studied epitaxially grown interfaces with element-selective near edge x-ray absorption fine structure. An extra peak is observed below the bulk edge onset for LiCl films on Cu and Ag substrates. The nature of chemical bonds as probed by x-ray photoemission spectroscopy and Auger electron spectroscopy remains unchanged, so we regard this as evidence for metal-induced gap states (MIGS) formed by the proximity to a metal, rather than local bonds at the interface. The dependence on the film thickness shows that the MIGS are as thin as one monolayer. An ab initio electronic structure calculation supports the existence of the MIGS that are strongly localized at the interface.
authors.affiliation: Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Kiguchi
authors.forename: Ryotaro
authors.initials: R
authors.lastname: Arita
authors.forename: Genki
authors.initials: G
authors.lastname: Yoshikawa
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Tanida
authors.forename: Masao
authors.initials: M
authors.lastname: Katayama
authors.forename: Koichiro
authors.initials: K
authors.lastname: Saiki
authors.forename: Atsushi
authors.initials: A
authors.lastname: Koma
authors.forename: Hideo
authors.initials: H
authors.lastname: Aoki