▎ 摘　　要

By carrying out a computation in the Lifshitz tight-binding one-electron model, we obtain the energy spectrum and electrical conductance of graphene, in the presence of substitutional impurity atoms, thus assessing the influence of the latter. In the weak-scattering approximation, we study specific features of the electron energy spectrum in the gap region having width eta vertical bar delta vertical bar and centered at the point y delta, arising because of the ordering of substitutional impurity atoms on nodes of the crystal lattice. Here eta is the parameter of ordering, delta is the difference of the scattering potentials of impurity atoms and carbon atoms, and y is the impurity concentration. It is shown that if the ordering parameter eta is close to eta(max) = 2y, y < 1/2, the plot of the density of electron states has peaks on the edges of the energy gap. Those peaks correspond to impurity levels. As the ordering parameter eta decreases, the impurity levels split into the impurity bands. The regions of localization of electron impurity states, which arise at the edges of the spectrum and edges of the energy gap, are investigated. (C) 2020 Elsevier B.V. All rights reserved.