MAGNETIC IMPURITIES ON GRAPHENE

MARCELO ROMERO; EDITH C. GOLDBERG

Buenos Aires

Conferencia; 27th International Conference on Low Temperature Physics; 2014

One natural way to induce a magnetic moment in a graphene sheet is to adsorbe magnetic impurities. Magnetic adatoms on graphene may give rise to a variety of many-body effects such as the Kondo effect [1].Recent studies of Co atoms adsorbed on graphene [2] show that upon approaching the surface, the ground-state configuration of Co undergoes several transitions, giving rise to two stable states. The first occurs at 3.1 A where the effects of the crystal field are negligible, and the second at 1.6 A, where these effects are appreciable.In the present work, we propose to use the results of these ab initio calculations within a model for the interaction between Co and graphene based on an extended Anderson Hamiltonian and the projection operator technique, which allow us to include the most probable charge and spin fluctuations in the Co atom [3]. The calculated low energy conductance spectra are compared with scanning tunneling spectroscopy measurements [1]. [1] M. F. Crommie et. al; Nature Physics 7, 43?47 (2011). [2] A. I. Lichtenstein et. al; Phys. Rev. B 86, 075422 (2012). [3] E. C. Goldberg and F. Flores, Phys. Rev. B 77, 125121 (2008).