Optical absorption rate in doped armchair graphene nanoribbon due to impurity atoms effects

We compute the optical absorption and density of states of disordered graphene armchair nanoribbon doped with impurity atoms in the context of tight binding model Hamiltonian. The effect of scattering by dilute charged impurities is discussed in terms of the self-consistent Born approximation. Green’s function approach has been implemented to find the behavior of density of states and optical absorption rate of armchair nanoribbon within linear response theory. Since optical absorption rate corresponds to imaginary part of dielectric function, the frequency behavior of optical absorption of graphene armchair nanoribbon has been investigated. Also the frequency behavior of optical absorption of graphene armchair nanoribbon has been studied due to impurity concentration and scattering potential strength. Our numerical results indicate that the frequency dependence of optical absorption shows an increasing behavior in terms of frequency at high impurity concentrations. Moreover the chemical potential dependence of imaginary part of dielectric function of disordered armchair nanoribbon with width 5 indicates that impurity concentration value has no considerable effect on this function at higher chemical potentials above 1.5 eV. Finally the dependence of optical absorption of nanoribbon on impurity concentration has been studied at fixed frequency and various scattering potential strengths.