We report on angle-resolved photoemission studies of the electronic pi states of high-quality epitaxial graphene layers on a Ni(111) surface. In this system the electron binding energy of the pi states shows a strong dependence on the magnetization reversal of the Ni film. The observed extraordinarily large energy shift up to 225 meV of the graphene-derived pi band peak position for opposite magnetization directions is attributed to a manifestation of the Rashba interaction between spin-polarized electrons in the pi band and the large effective electric field at the graphene/Ni interface. Our findings show that an electron spin in the graphene layer can be manipulated in a controlled way and have important implications for graphene-based spintronic devices.

The electronic structure of the zero-gap two-dimensional graphene has a charge neutrality point exactly at the Fermi level that limits the practical application of this material. There are several ways to modify the Fermi-level-region of graphene, e.g. adsorption of graphene on different substrates or different molecules on its surface. In all cases the so-called dispersion or van der Waals interactions can play a crucial role in the mechanism, which describes the modification of electronic structure of graphene. The adsorption of water on graphene is not very accurately reproduced in the standard density functional theory (DFT) calculations and highly-accurate quantum-chemical treatments are required. A possibility to apply wavefunction-based methods to extended systems is the use of local correlation schemes. The adsorption energies obtained in the present work by means of CCSD(T) are much higher in magnitude than the values calculated with standard DFT functional although they agree that physisorption is observed. The obtained results are compared with the values available in the literature for binding of water on the graphene-like substrates.

We report an element-specific investigation of electronic and magnetic properties of the graphene/Ni(111) system. Using x-ray magnetic circular dichroism, the occurrence of an induced magnetism of the carbon atoms in the graphene layer is observed. We attribute this magnetic moment to the strong hybridization between C π and Ni 3d valence band states. The net magnetic moment of carbon in the graphene layer is estimated to be in the range of 0.05 − 0.1

The article presents the work on the investigation of the surface structure as well as electronic and magnetic properties of graphene layer on a lattice matched surface of a ferromagnetic material, Ni(111). Scanning tunneling microscopy imaging shows that perfectly ordered epitaxial graphene layers can be prepared by elevated temperature decomposition of hydrocarbons, with domains larger than the terraces of the underlying Ni(111). In some exceptional cases graphene films do not show rotational alignment with the metal surface leading to moiré structures with small periodicities. We give a detailed analysis of the crystallographic structure of graphene with respect to the Ni(111) surface based both on experimental results and recent theoretical studies. X-ray absorption spectroscopy investigations of empty valence band states demonstrate the existence of interface states which originate from the strong hybridization between the graphene π and Ni 3d valence-band states with the partial charge transfer of the spin-polarized electrons to the graphene π * unoccupied states. The latter leads to the appearance of an induced magnetic moment of carbon atoms in the graphene layer which is unambiguously confirmed by both xray magnetic circular dichroism and spin-resolved photoemission. Further angleresolved photoemission investigations indicate a strong interaction between graphene and Ni (111) showing considerable modification of the valence-band states of Ni and graphene due to a strong hybridization. The detailed analysis of the Fermi surface of the graphene/Ni(111) system show very good agreement between experimental and calculated two-dimensional maps of the electronic states around the Fermi level confirming the main predictions of the theory. We analyze our spectroscopic results relying on the currently available band structure calculations for the graphene/Ni(111) system and discuss the perspectives of the realization of graphene/ferromagnet-based devices.