Unconventional optical response in monolayer graphene upon dominant intraband scattering

Scattering dynamics influence the graphenes transport properties and inhibits the charge carrier deterministic behaviour. The intra or inter-band scattering mechanisms are vital for graphenes optical conductivity response under specific considerations of doping. Here, we investigated the influence of scattering systematically on optical conductivity using a semi-classical multiband Boltzmann equation with inclusion of both electron-electron & electron-phonon collisions. We found unconventional characteristics of linear optical response with a significant deviation from the universal conductivity e^2/4ħ in doped monolayer graphene. This is explained through phenomenological relaxation rates under low doping regime with dominant intraband scattering. Such novel optical responses are vanished at high temperatures or overdoping conditions due to strong Drude behaviour. With the aid of approximations around Dirac points we have developed analytical formalism for many body interactions and is in good agreement with the Kubo approaches.