title: Bi ordered phases on Cu(100): periodic arrays of dislocations influence the electronic properties.
abstract: A single layer of bismuth deposited on the Cu(100) surface forms long range ordered structural phases at various Bi density. A highly ordered c(2 x 2) reconstruction is accomplished at 0.5 ML, further Bi deposition induces a c(9square root of 2 x square root of 2)R45 degrees structure and a subsequent p(10 x 10) phase related to the formation of regular dislocations arrays. The transition from a c(2 x 2) superstructure to the c(9square root of 2 x square root of 2)R45 degrees phase is accompanied by a sudden decrease in the work function. Photoemission measurements reveal that the Bi induced states close to the Fermi level, associated to the c(2 x 2) phase, are strongly quenched when the arrays of dislocations are formed, while at higher binding energies, they undergo an energy shift probably due to a confinement effect. The low-energy single particle excitations and the electron dispersion of the Bi induced states of the c(2 x 2) phase are compared to the electronic states deduced by theoretical band structure obtained by ab initio calculation performed within the embedding method applied to a realistic semi-infinite system.
authors.affiliation: Dipartimento di Fisica, Università di Roma La Sapienza, Piazzale A. Moro 5, I-00185 Roma, Italy. pierluigi.gargiani@roma1.infn.it
authors.forename: Pierluigi
authors.initials: P
authors.lastname: Gargiani
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Izzo
authors.forename: Fabio
authors.initials: F
authors.lastname: Bussolotti
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Betti
authors.forename: S
authors.initials: S
authors.lastname: Achilli
authors.forename: M I
authors.initials: MI
authors.lastname: Trioni