title: Chemisorption-induced gap state at organic-metal interface: Benzenethiol on Pt(111).
abstract: Electron emission spectra obtained by thermal collisions of He*(2(3)S) metastable atoms with benzenethiol (C(6)H(5)SH) on Pt(111) were measured to characterize the chemisorption-induced gap state (CIGS) formed at the organic-metal interface. First-principles calculations using density functional theory were also performed for an ordered thiolate (C(6)H(5)S) monolayer on Pt(111). Our data exhibit that the CIGS due to the S 3p-Pt 5d mixings appears just below the Fermi level (E(F)) of the substrate, where the local density of states decreases drastically from the S terminal to the benzene ring. Furthermore, strong benzene pi(1e(1g))-S 3p couplings are apparently lifted upon the formation of thiolate. These features indicate that thiolate is not a good mediator of metal wave functions at E(F), which is closely related to tunneling probability (and eventually electric conductance) in the relevant metal-organic-metal junctions at zero bias.
authors.affiliation: Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro, Tokyo 153-8902, Japan. masuda@piesap.c.u-tokyo.ac.jp
authors.forename: Shigeru
authors.initials: S
authors.lastname: Masuda
authors.forename: Toyohiro
authors.initials: T
authors.lastname: Kamada
authors.forename: Keita
authors.initials: K
authors.lastname: Sasaki
authors.forename: Masaru
authors.initials: M
authors.lastname: Aokia
authors.forename: Yoshitada
authors.initials: Y
authors.lastname: Morikawa