Impurity states in graphene with intrinsic spin-orbit interaction

We consider the problem of electron energy states related to strongly localized potential of a single impurity in graphene. Our model simulates the effect of impurity atom substituting the atom of carbon, on the energy spectrum of electrons near the Dirac point. We take into account the internal spin-orbit interaction, which can modify the structure of electron bands at very small neighborhood of the Dirac point, leading to the energy gap. This makes possible the occurrence of additional impurity states in the vicinity of the gap.