Magnetic moment and anisotropy of individual Co atoms on graphene.
We report on the magnetic properties of single Co atoms on graphene on Pt(111). By means of scanning tunneling microscopy spin-excitation spectroscopy, we infer a magnetic anisotropy of K=-8.1  meV with out-of-plane hard axis and a magnetic moment of 2.2μ(B). Co adsorbs on the sixfold graphene hollow site. Upon hydrogen adsorption, three differently hydrogenated species are identified. Their magnetic properties are very different from those of clean Co. Ab initio calculations support our results and reveal that the large magnetic anisotropy stems from strong ligand field effects due to the interaction between Co and graphene orbitals.
Institute of Condensed Matter Physics (ICMP), Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015, Switzerland.
F
F
Donati
Institute of Condensed Matter Physics (ICMP), Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015, Switzerland.
Q
Q
Dubout
Institute of Theoretical Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
G
G
Autès
Institute of Condensed Matter Physics (ICMP), Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015, Switzerland.
F
F
Patthey
Institute of Condensed Matter Physics (ICMP), Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015, Switzerland and Madrid Institute for Advanced Studies, IMDEA Nanoscience, Calle Faraday 9, Campus Cantoblanco, E-28049 Madrid, Spain.
F
F
Calleja
Institute of Condensed Matter Physics (ICMP), Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015, Switzerland and Catalan Institute of Nanoscience and Nanotechnology (ICN2), UAB Campus, E-08193 Barcelona, Spain and Department of Materials, ETH Zurich, CH-8093 Zurich, Switzerland.
P
P
Gambardella
Institute of Theoretical Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
O V
OV
Yazyev
Institute of Condensed Matter Physics (ICMP), Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015, Switzerland.
H
H
Brune