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

Hao Tang (1) , Nathalie Tarrat (2) , Véronique Langlais (3) , Yongfeng Wang (4)

1 CEMES - Centre d'élaboration de matériaux et d'études structurales
2 CEMES-SINanO - Surfaces, Interfaces et Nano-Objets
3 CEMES-GNS - Groupe NanoSciences
4 Peking University [Beijing]

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.

Mots clés: spin states; spin switch; activation barrier; density functional theory; iron tetraphenylporphyrin

Domaines: Chimie-Physique [physics.chem-ph]; Chimie; Physique [physics]

Hao Tang, Nathalie Tarrat, Véronique Langlais, Yongfeng Wang. Adsorption of iron tetraphenylporphyrin on (111) surfaces of coinage metals: a density functional theory study. Beilstein Journal of Nanotechnology, 2017, 8, pp.2484 - 2491. ⟨10.3762/bjnano.8.248⟩. ⟨hal-01755496⟩