Cobalt atoms drive the anchoring of Co-TPP molecules to the oxygen-passivated Fe(0 0 1) surface

• Published in: Applied surface science Vol. 505; p. 144213
• Main Authors: Calloni, A., Jagadeesh, M.S., Bussetti, G., Fratesi, G., Achilli, S., Picone, A., Lodesani, A., Brambilla, A., Goletti, C., Ciccacci, F., Duò, L., Finazzi, M., Goldoni, A., Verdini, A., Floreano, L.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-03-2020
• Subjects: Co-TPP; Fe(0 0 1)-p(1×1)O; IPES; NEXAFS; Photoemission; Ultra-thin metal-oxide interface; Ultra-thin metal-oxide interface; Fe(0 0 1)-p(1×1)O; NEXAFS; Co-TPP; Photoemission; IPES
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2019.144213

•A photoemission and X-ray adsorption analysis of Co-TPP films on Fe(0 0 1)-p(1 × 1)O.•A commensurate superstructure is found with Co-TPP molecules on Fe(0 0 1)-p(1 × 1)O.•The Co-TPP/substrate interaction is localized on the Co(II) ion.
We present a multitechnique investigation of the structural and electronic properties of the prototypical system composed by ultra-thin films of magnetic molecules [Co-tetraphenyl-porphyrins (Co-TPP)] grown on a ferromagnetic substrate [oxygen passivated Fe(0 0 1), namely the Fe(0 0 1)-p(1 × 1)O surface]. Low Energy electron diffraction (LEED) and scanning tunneling microscopy (STM), coupled with first-principles calculations, reveal the formation of a commensurate superstructure at monolayer coverage, made by a square array of flat-lying TPP molecules. UV–photoemission and inverse photoemission spectroscopies (UPS and IPES) are used to investigate their electronic structure. Similar to our previous results on the Zn–TPP growth on Fe(0 0 1)–p(1 × 1)O, the passivation of the metallic surface is able to preserve the photoemission features characteristic of quasi-free molecules, opening the route towards an exploitation of single oxide layers as protective films in organic/inorganic junctions. X-ray photoemission (XPS) and near edge X-ray adsorption fine structure spectroscopies (NEXAFS), are used to reveal the details of the Co–TPP interaction with the substrate.