Charge transfer between atoms and Graphene surfaces: electron repulsion in the atom state and band structure details

ROMERO, MARCELO A.; DOBRY, ARIEL; GOLDBERG, EDITH C.

Valparaíso, CHILE

Congreso; Solidos 2009; 2009

We present a calculation of the different charge configurations probabilities in an atom adsorbed on a surface. These configurations are taken into account through a method based on the use of projectors in the Anderson-Newns model. The probabilities of occurrence of the different charge states, as well as the density of states projected on the atom are calculated using appropriate Green´s functions solved using the equations of motion method (EOM). A mean field type approximation is made to close the equations of motion in a strict second order in the hopping parameter. Graphene is solved through a tigth-binding approximation, which gives us the wave function that describes the states of this two-dimensional solid. In this way we can incorporate the full details of the electronic structure of graphene in the description of the self-energy that define the atom-surface interaction.In particular we study the Li/Graphene system, since Li has ionization energy that almost lies close to the Fermi energy of the surface. It’s around this energy where the effect of the peculiarities of the band structure is expected to be more significant. A realistic calculation of the required parameters for this particular system is done through the bond-pair method previously developed in our group.