title: Electronic properties of epitaxial cerium oxide films during controlled reduction and oxidation studied by resonant inelastic X-ray scattering.
abstract: We investigated the evolution of the electronic structure of cerium oxide ultrathin epitaxial films during reduction and oxidation processes using resonant inelastic X-ray scattering at the Ce L3 absorption edge, a technique sensitive to the electronic configurations at the 4f levels and in the 5d band thanks to its high energy resolution. We used thermal treatments in high vacuum and in oxygen partial pressure to induce a controlled and reversible degree of reduction in cerium oxide ultrathin epitaxial films of different thicknesses. Two dominant spectral components contribute to the measured spectra at the different degrees of oxidation/reduction. In ultrathin films a modification of the electronic properties associated with platinum substrate proximity and with dimensionality is identified. The different electronic properties induce a higher reducibility in ultrathin films, ascribed to a decrease of the surface oxygen vacancy formation energy.
authors.affiliation: Dipartimento di Scienze Fisiche Informatiche e Matematiche, Università degli Studi di Modena e Reggio Emilia, Via G. Campi 213/a, 41125 Modena, Italy and Istituto Nanoscienze, Consiglio Nazionale delle Ricerche, Via G. Campi 213/a, 41125 Modena, Italy. paola.luches@nano.cnr.it.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Gasperi
authors.affiliation: European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble, France.
authors.forename: Lucia
authors.initials: L
authors.lastname: Amidani
authors.affiliation: Dipartimento di Scienze Fisiche Informatiche e Matematiche, Università degli Studi di Modena e Reggio Emilia, Via G. Campi 213/a, 41125 Modena, Italy and Istituto Nanoscienze, Consiglio Nazionale delle Ricerche, Via G. Campi 213/a, 41125 Modena, Italy. paola.luches@nano.cnr.it.
authors.forename: Francesco
authors.initials: F
authors.lastname: Benedetti
authors.affiliation: Department of Physics and Astronomy, University of Bologna, Viale C. Berti Pichat 6/2, 40127 Bologna, Italy and Istituto Officina dei Materiali, Consiglio Nazionale delle Ricerche, Operative Group in Grenoble, c/o ESRF, BP 220, F-38043 Grenoble, France.
authors.forename: Federico
authors.initials: F
authors.lastname: Boscherini
authors.affiliation: European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble, France.
authors.forename: Pieter
authors.initials: P
authors.lastname: Glatzel
authors.affiliation: Dipartimento di Scienze Fisiche Informatiche e Matematiche, Università degli Studi di Modena e Reggio Emilia, Via G. Campi 213/a, 41125 Modena, Italy and Istituto Nanoscienze, Consiglio Nazionale delle Ricerche, Via G. Campi 213/a, 41125 Modena, Italy. paola.luches@nano.cnr.it.
authors.forename: Sergio
authors.initials: S
authors.lastname: Valeri
authors.affiliation: Istituto Nanoscienze, Consiglio Nazionale delle Ricerche, Via G. Campi 213/a, 41125 Modena, Italy. paola.luches@nano.cnr.it.
authors.forename: Paola
authors.initials: P
authors.lastname: Luches