title: Ultrathin wagon-wheel-like TiOx phases on Pt(111): a combined low-energy electron diffraction and scanning tunneling microscopy investigation.
abstract: Ultrathin ordered titanium oxide films on a Pt(111) surface have been prepared by reactive deposition and characterized by low-energy electron diffraction and scanning tunneling microscopy (STM). According to the postdeposition annealing condition, three different phases have been prepared which show a wagon-wheel-like (hereafter ww) morphological pattern. Two of them can be prepared as single phases (w- and w'-TiO(x)) and one (w(int)-TiO(x)) as a mixed phase which always coexists with at least one of the other two phases. All of them are formed by a Ti-O bilayer, where the Ti atoms are located at the interface with the substrate, but they show a rather distinct STM ww pattern. The experimental STM contrast has been discussed on the basis of a Moiré-like model, i.e., as deriving from a modulation of the Ti occupancy of the different substrate sites (i.e., hollow, bridge and on-top sites). The major part of the STM data can be easily interpreted on the basis of this simplified model.
authors.affiliation: Dipartimento di Scienze Chimiche and Unità di Ricerca INFM-CNR and INSTM, Università di Padova, Via Marzolo, I-35131 Padova, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Sedona
authors.forename: Stefano
authors.initials: S
authors.lastname: Agnoli
authors.forename: Gaetano
authors.initials: G
authors.lastname: Granozzi