Localized spins on graphene

P. S. CORNAGLIA; GONZALO USAJ; C. A. BALSEIRO

PHYSICAL REVIEW LETTERS

AMER PHYSICAL SOC

Año: 2009 vol. 102 p. 46801 - 46801

0031-9007

   The problem of a magnetic impurity, atomic or molecular, absorbed on top of a carbon atom in otherwise clean graphene is studied using the numerical renormalization group. The spectral, thermody-namic, and scattering properties of the impurity are described in detail. In the presence of a small magnetic field, the low-energy electronic features of graphene make it possible to inject spin-polarized currents through the impurity using a scanning tunneling microscope. Furthermore, the impurity scattering becomes strongly spin dependent and for a finite impurity concentration it leads to spin-polarized bulk currents and a large magnetoresistance. In gated graphene the impurity spin is Kondo screened at low temperatures. However, at temperatures larger than the Kondo temperature, the anomalous magnetotran- sport properties are recovered.