Optical conductivity of AA-stacked bilayer graphene in presence of bias voltage beyond Dirac approximation

Abstract

We have addressed the dynamical conductivity of AA-stacked bilayer graphene as a function of photon frequency in the presence of a finite bias voltage at finite temperature. Using linear response theory and Green’s function approach, the frequency dependence of optical conductivity has been obtained in the context of tight binding model Hamiltonian. Our results show a finite Drude absorption at low frequency for the case of charge neutrality. However, Drude weight gets remarkable amount at unbiased case. We have studied the behavior of optical spectra as a function of chemical potential for different values of bias voltages. Dynamical conductivity is found to be monotonically decreasing with chemical potential due to increased scattering among electrons at higher chemical potential. Furthermore the dependence of optical conductivity on the voltage bias and temperature has been investigated in details.