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Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Graphene on ferromagnetic surfaces and its functionalization with water and ammonia | Bõttcher et al. Nanoscale Research Letters 2011 6 214 http www.nanoscalereslett.eom content 6 1 214 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Graphene on ferromagnetic surfaces and its functionalization with water and ammonia 1.2 1 1 1 2 2 Stefan Bottcher Martin Weser Yuriy S Dedkov Karsten Horn Elena N Voloshina Beate Paulus Abstract In this article an angle-resolved photoelectron spectroscopy ARPES X-ray absorption spectroscopy XAS and density-functional theory DFT investigations of water and ammonia adsorption on graphene Ni 111 are presented. The results of adsorption on graphene Ni 111 obtained in this study reveal the existence of interface states originating from the strong hybridization of the graphene n and spin-polarized Ni 3d valence band states. ARPES and XAS data of the H2O NH3 graphene Ni 111 system give an information regarding the kind of interaction between the adsorbed molecules and the graphene on Ni 111 . The presented experimental data are compared with the results obtained in the framework of the DFT approach. Introduction Graphene is a single layer of carbon atoms arranged in a honeycomb lattice with two crystallographically equivalent atoms C1 and C2 in its primitive unit cell 1 2 . The sp 1 2 hybridization between one 2s orbital and two 2p orbitals leads to a trigonal planar structure with a formation of strong X bonds between carbon atoms that are separated by 1.42 Ả. These bands have a filled shell and hence form a deep valence band. The unaffected 2pz orbital which is perpendicular to the planar structure of the graphene layer can bind covalently with neighboring carbon atoms leading to the formation of a n band. Since each 2pz orbital has one extra electron the n band is half filled. The n and n bands touch in a single point at the Fermi energy F at the corner of the hexagonal graphene s Brillouin zone and close to this so-called Dirac point the bands display a linear dispersion and form perfect Dirac
