▎ 摘　　要

In this work, the effect of coupling between metallic electrodes and graphene is discussed. We demonstrate that the transport properties of graphene at the charge neutrality point are very sensitive to this coupling. By introducing a model based on two real parameters, namely the real and the imaginary parts of the self-energy which describes the metal-graphene coupling, the obtained results of charge conductivity versus the Fermi energy reproduce well the essential features of experimental data such as the asymmetry between electrons and holes. Additionally, the possible role of scattering processes in the enhancement of the density of states, and thus of the minimum of conductivity, at the charge neutrality point is also discussed. This work is believed to be helpful for further studies of graphene-based devices wherein metallic electrodes may have a major impact on electrical characteristics.