Impurezas magnéticas na rede cristalina tipo grafeno

Abstract

This work presents a detailed study of a model Hamiltonian for magnetic impurities on a graphene-like material. The graphene-like model consists of a honeycomb lattice with different Hubbard interactions for each sublattice. A simple, but well known method for describing magnetic impurities on metals, namely the Anderson Model, has been used. Retarded Green’s function and equation of motion is used to find impurity’s mean occupancy and dimensionless conductance. The numerical values of the mean occupancy and dimensionless conductance are calculated in the low-energy limit and near zero temperature. Mean occupancy shows dependencies on the energy of the impurity level and also the hybridization interaction of the impurity and the lattice. The Coulomb interaction parameter of the lattice does not affect the magnetic limits of the system. The dimensionless conductance, also calculated numerically at the same limit, presents non-zero finite values depending on the chemical potential. The graph of conductance as a function of the chemical potential shows distinct spikes located at the transition of magnetic and non-magnetic states.