Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801, USA.
Phys Rev Lett. 2009 Nov 13;103(20):206804. doi: 10.1103/PhysRevLett.103.206804. Epub 2009 Nov 11.
We examine theoretically the signatures of magnetic adatoms in graphene probed by scanning tunneling spectroscopy (STS). When the adatom hybridizes equally with the two graphene sublattices, the broadening of the local adatom level is anomalous and can scale with the cube of the energy. In contrast to ordinary metal surfaces, the adatom local moment can be suppressed by the proximity of the probing scanning tip. We propose that the dependence of the tunneling conductance on the distance between the tip and the adatom can provide a clear signature for the presence of local magnetic moments. We also show that tunneling conductance can distinguish whether the adatom is located on top of a carbon atom or in the center of a honeycomb hexagon.
我们从理论上研究了扫描隧道谱（STS）探测石墨烯中磁 adatoms 的特征。当 adatoms 与两个石墨烯子晶格同等程度地杂化时，局域 adatoms 能级的展宽是反常的，并且可以与能量的立方成正比。与普通金属表面不同，局域 adatoms 磁矩可以被探测扫描针尖的临近所抑制。我们提出，针尖和 adatoms 之间的距离对隧道电导的依赖关系可以为局域磁矩的存在提供明确的特征。我们还表明，隧道电导可以区分 adatoms 是位于碳原子的顶部还是蜂窝六边形的中心。
