title: Vacancy formation on C60/Pt (111): unraveling the complex atomistic mechanism.
abstract: The interaction of fullerenes with transition metal surfaces leads to the development of an atomic network of ordered vacancies on the metal. However, the structure and formation mechanism of this intricate surface reconstruction is not yet understood at an atomic level. We combine scanning tunneling microscopy, high resolution and temperature programmed-x-ray photoelectrons spectroscopy, and density functional theory calculations to show that the vacancy formation in C60/Pt(111) is a complex process in which fullerenes undergo two significant structural rearrangements upon thermal annealing. At first, the molecules are physisorbed on the surface; next, they chemisorb inducing the formation of an adatom-vacancy pair on the side of the fullerene. Finally, this metastable state relaxes when the adatom migrates away and the vacancy moves under the molecule. The evolution from a weakly-bound fullerene to a chemisorbed state with a vacancy underneath could be triggered by residual H atoms on the surface which prevent a strong surface-adsorbate bonding right after deposition. Upon annealing at about 440 K, when all H has desorbed, the C60 interacts with the Pt surface atoms forming the vacancy-adatom pair. This metastable state induces a small charge transfer and precedes the final adsorption structure.
authors.affiliation: ESISNA Group Instituto de Ciencia de Materiales de Madrid (CSIC), c/ Sor Juana Inés de la Cruz, E-28049 Madrid, Spain.
authors.forename: Anna L
authors.initials: AL
authors.lastname: Pinardi
authors.forename: Giulio
authors.initials: G
authors.lastname: Biddau
authors.forename: Kees
authors.initials: K
authors.lastname: van De Ruit
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Otero-Irurueta
authors.forename: Sara
authors.initials: S
authors.lastname: Gardonio
authors.forename: Silvano
authors.initials: S
authors.lastname: Lizzit
authors.forename: Robert
authors.initials: R
authors.lastname: Schennach
authors.forename: Cees F J
authors.initials: CF
authors.lastname: Flipse
authors.forename: María F
authors.initials: MF
authors.lastname: López
authors.forename: Javier
authors.initials: J
authors.lastname: Méndez
authors.forename: Rubén
authors.initials: R
authors.lastname: Pérez
authors.forename: José A
authors.initials: JA
authors.lastname: Martín-Gago