Institute of Condensed Matter Physics (ICMP), Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 3, CH-1015, Switzerland.
Institute of Theoretical Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
Phys Rev Lett. 2013 Dec 6;111(23):236801. doi: 10.1103/PhysRevLett.111.236801. Epub 2013 Dec 3.
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.
我们报告了在 Pt(111)上石墨烯上单钴原子的磁性。通过扫描隧道显微镜自旋激发谱，我们推断出具有面外硬轴的磁各向异性为 K=-8.1 meV 和磁矩为 2.2μ(B)。Co 吸附在六重石墨烯的空位点上。在氢气吸附后，我们识别出三种不同的氢化物。它们的磁性与清洁的 Co 有很大的不同。从头算计算支持我们的结果，并表明大的磁各向异性源于由于 Co 和石墨烯轨道之间的相互作用导致的强配体场效应。
