Molecular tilting and columnar stacking of Fe phthalocyanine thin films on Au(111)

Scanning tunneling microscopy and x-ray absorption spectroscopic results at the Fe K edge of Fe phthalocyanine (FePc) thin films grown on Au substrates, together with theoretical calculations, allow us to refine the structure of the film. In particular, we show that the columnar stacking of the FePc molecules is different from that found in bulk ¿ and ß phases. Moreover, the molecules do not lay parallel to the surface of the substrate. These structural findings are relevant to understand magnetism of FePc films.The financial support of the Spanish financial agency MINECO MAT2011-2379 and MAT2014-53921-R, Aragonese DGA-IMANA E34 (co-funded by European Social Fund), as well as European Union FEDER funds is acknowledged. The sample preparation and initial structural characterization were supported by the Office of Basic Energy Science, U.S. Department of Energy, BES-DMS funded by the Department of Energy’s Office of Basic Energy Science, DMR under Grant No. DE FG03 87ER-45332 and NSF DMR 0847552.Peer Reviewe

Publisher Correction : Real space manifestations of coherent screening in atomic scale Kondo lattices

Aquesta és una correcció a l'article 10.1038/s41467-019-10103-

Molecular tilting and columnar stacking of Fe phthalocyanine thin films on Au(111)

Scanning tunneling microscopy and x-ray absorption spectroscopic results at the Fe K edge of Fe phthalocyanine (FePc) thin films grown on Au substrates, together with theoretical calculations, allow us to refine the structure of the film. In particular, we show that the columnar stacking of the FePc molecules is different from that found in bulk a and ß phases. Moreover, the molecules do not lay parallel to the surface of the substrate. These structural findings are relevant to understand magnetism of FePc films

On-Surface Driven Formal Michael Addition Produces m-Polyaniline Oligomers on Pt(111)

On-surface synthesis is emerging as a highly rational bottom-up methodology for the synthesis of molecular structures that are unattainable or complex to obtain by wet chemistry. Here, oligomers of meta-polyaniline, a known ferromagnetic polymer, were synthesized from para-aminophenol building-blocks via an unexpected and highly specific on-surface formal 1, 4 Michael-type addition at the meta position, driven by the reduction of the aminophenol molecule. We rationalize this dehydrogenation and coupling reaction mechanism with a combination of in situ scanning tunneling and non-contact atomic force microscopies, high-resolution synchrotron-based X-ray photoemission spectroscopy and first-principles calculations. This study demonstrates the capability of surfaces to selectively modify local molecular conditions to redirect well-established synthetic routes, such as Michael coupling, towards the rational synthesis of new covalent nanostructures

Searching for kagome multi-bands and edge states in a predicted organic topological insulator

This is the final version. Available on open access from the Royal Society of Chemistry via the DOI in this recordRecently, mixed honeycomb-kagome lattices featuring metal-organic networks have been theoretically proposed as topological insulator materials capable of hosting nontrivial edge states. This new family of so-called "organic topological insulators" are purely two-dimensional and combine polyaromatic-flat molecules with metal adatoms. However, their experimental validation is still pending given the generalized absence of edge states. Here, we generate one such proposed network on a Cu(111) substrate and study its morphology and electronic structure with the purpose of confirming its topological properties. The structural techniques reveal a practically flawless network that results in a kagome network multi-band observed by angle-resolved photoemission spectroscopy and scanning tunneling spectroscopy. However, at the network island borders we notice the absence of edge states. Bond-resolved imaging of the network exhibits an unexpected structural symmetry alteration that explains such disappearance. This collective lifting of the network symmetry could be more general than initially expected and provide a simple explanation for the recurrent experimental absence of edge states in predicted organic topological insulators.Spanish Ministry of Economy, Industry and Competitiveness (MINECO)Ministry of Science and Innovation (MICINN)Government of AragonFormación de Personal InvestigadorGovernment of the Basque CountryEuropean Regional Development Fund (ERDF)Royal Societ

Tuning the magnetic moment of high density FePc/Ag(110) phases by oxygen dosing

Resumen del trabajo presentado a la 64th Annual Conference on Magnetism and Magnetic Materials (MMM), celebrada en Las Vegas (USA) del 4 al 8 de noviembre de 2019.Peer reviewe

X-ray-Induced Reversible Switching of an Azobenzene Derivative Adsorbed on Bi(111)

We report on the adsorption of a submonolayer of di-m-cyanoazobenzene (DMC) on Bi(111) and on the reversible switching of these molecules induced by resonant X-ray illumination. DMC adsorbs in at least two configurations, the flat trans and the nonflat cis isomer. We find that in 0.8 monolayers at least 26% of the molecules change their configuration at 110 K by excitation of the N1s → LUMO transition at the azo group, and by a thermally induced back reaction at 120 K. Nonresonant excitation with X-ray light does not induce any reversible changes

Manganese phthalocyanine derivatives synthesized by on-surface cyclotetramerization

et al.We report a two-step on-surface synthesis of Mn phthalocyanine molecules from four tetracyanobenzene (TCNB) monomers through coordinative bonding with manganese adatoms. In the first step, the coevaporation of TCNB and Mn atoms leads to a metal-organic network stabilized by a combination of coordination and hydrogen (H) bonds. In the second step, annealing the coordination networks above room temperature results in individual Mn phthalocyanine molecules. The results shown here demonstrate the viability of an on-surface chemical synthesis strategy involving the reduction of the organic reagents by metal ions to produce metal-organic molecules. © 2014 American Chemical Society.Financial support by the Spanish Ministry of Science through Plan Nacional de I+D+i grant MAT2010-19236, University of Zaragoza (JIUZ-2013-CIE-12), and the German Academic Exchange Program (DAAD) is acknowledged.Peer Reviewe

Direct observation of gradual molecular level alignment of Fe Pcs on a gold electrode

Resumen del póster presentado a la Conferencia bienal Fuerzas y Túnel, celebrada en Jaca (España) del 27 al 29 de junio de 2018.One of the key prerequisite for the optimal performance of organic opto-electronic devices is an efficient charge-carrier transport into and out of the organic semiconductor material. Carrier injection in turn strongly depends on the molecular level alignment of the organic semiconductor material against the fermi level of the conducting electrodes. In a recent work we studied the evolution of molecular levels of Fe-phthalocyanine with increasing layer thickness on a gold (111) surface. By means of STM and STS we found that beyond the strong hybridization of the electronic states of the 1st molecular monolayer with the metallic substrate, the gap between the frontier orbitals is still strongly influenced at the 5th mono layer away from the surface. This sequential decrease of the HOMO-LUMO gap towards the metallic electrode should strongly support the charge-carrier injection for this kind of materials. Accordingly, such a layer- wise STM/STS investigation can give a detailed atomistic insight into electronic processes at metal/organic interfaces towards the bulk material and might help to improve the design of organic opto-electronic devices.Peer Reviewe