Effects of electron-impurity scattering on density of states in   silicene: impurity bands and band-gap narrowing
  Considering the interband correlation, we present a generalized multiple-scattering approach of Green's function to investigate the effects of electron-impurity scattering on the density of states in silicene. The reduction of energy gaps in the case of relatively high chemical potential and the transformation of split-off impurity bands into band tails for low chemical potential are found. The dependency of optical conductivity on the impurity concentration is also discussed for frequency within the terahertz regime. 
S. Y. Liu, Y. C. Zeng, and X. L. Lei
cond-mat.mtrl-sci cond-mat.dis-nn cond-mat.mes-hall