Dynamic conductivity of graphene with electron-LO-phonon interaction

We calculate the electrical conductivity of single-layer graphene within the regime of massless Dirac fermions. We consider the electron-LO-phonon interactions as the dominant scattering mechanism. By using the Green's-function method, we are able to obtain the quantitative contribution from the five leading diagrams in the high-frequency approximation. It is found that electron-LO-phonon interactions cause an increase to the electromagnetic absorption of single-layer graphene of as much as 20% at room temperature. The spectrum is dominated by a continuum contribution with a peak at omega=omega(LO)/2 and represents intraband transitions. The temperature and doping dependence of these peak corrections is also investigated. These results probe the validity of the universal conductivity of graphene with respect to electron-phonon interactions under a range of conditions.