Centre d’Élaboration de Matériaux et d’Etudes Structurales (UPR 8011)

Accueil > Recherche > SINanO : Surfaces, Interfaces et Nano-Objets > Thématiques de Recherche

Self-assembling and self-organization at surfaces

SINanO Highlights - The names of the team members are in blue

Adsorption of iron tetraphenylporphyrin on (111) surfaces of coinage metals : a density functional theory study

Hao Tang, Nathalie Tarrat, Véronique Langlais and Yongfeng Wang

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The adsorption of the iron tetraphenylporphyrin (FeTPP) molecule in its deckchair conformation was investigated on Au(111), Ag(111) and Cu(111) surfaces by performing spin-polarized density functional theory (DFT) calculations taking into account both van der Waals (vdW) interaction and on-site Coulomb repulsion. The deckchair conformation of the molecule favours intermolecular π–π-type interactions in a less densely packed monolayer than the saddle conformation. The activation barrier between the two stable magnetic states (high spin, S = 2 and intermediate spin, S = 1) of the molecule in vacuum disappears upon adsorption on the metal surfaces. The high-spin state of physisorbed FeTPP is stable on all adsorption sites. This result reveals that an external permanent element such as a STM tip or an additional molecule is needed to use FeTPP or similar molecules as model system for molecular spin switches.


Robust Sierpinski triangle fractals on symmetry-mismatched Ag(100)

X. Zhang, N. Li, L. Liu, G. Gu, C. Li, H. Tang, L. Peng, S. Hou and Y. Wang

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Sierpinski triangle fractals were constructed on both Ag(111) andsymmetry-mismatched fourfold Ag(100) surfaces through chemical reaction between H3PH molecules and Fe atoms under vacuum. Density functional theory calculations revealed that the fractals were stabilized by the strong coordination interaction between Fe and O atoms. In comparison, pure H3PH molecules formed fractals via moderately strong hydrogen bonds only on Ag(111), not on Ag(100).