Electron waves in chemically substituted grapheneN. M. R. Peres1, F. D. Klironomos2, S.-W. Tsai2, J. R. Santos1, J. M. B. Lopes dos Santos3 and A. H. Castro Neto4
1 Center of Physics and Departament of Physics, Universidade do Minho - P-4710-057, Braga, Portugal
2 Department of Physics and Astronomy, University of California - Riverside, CA 92521, USA
3 CFP and Departamento de Física, Faculdade de Ciências Universidade de Porto - 4169-007 Porto, Portugal
4 Department of Physics, Boston University - 590 Commonwealth Avenue, Boston, MA 02215, USA
received 29 August 2007; accepted in final form 21 October 2007; published December 2007
published online 13 November 2007
We present exact analytical and numerical results for the electronic spectra and the Friedel oscillations around a substitutional impurity atom in a graphene lattice. A chemical dopant in graphene introduces changes in the on-site potential as well as in the hopping amplitude. We employ a T-matrix formalism and find that disorder in the hopping introduces additional interference terms around the impurity that can be understood in terms of bound, semi-bound, and unbound processes for the Dirac electrons. These interference effects can be detected by scanning tunneling microscopy.
73.20.Hb - Impurity and defect levels; energy states of adsorbed species.
73.23.-b - Electronic transport in mesoscopic systems.
81.05.Uw - Carbon, diamond, graphite.
© EPLA 2007