Uncovering the dominant scattering mechanism in graphene system

We re-investigate the impact of possible scattering mechanism on quantum transport properties in graphene. For Coulomb scatters, conductivity-carrier-dependence σ(n) away from the Dirac point can vary from sub-linear to linear behavior with increasing the impurity concentration, which is consistent with the existed experimental observations. For comparison, we also confirm that the resonant impurities or ripples cannot produce a linear behavior conductivity-carrier-dependence. Therefore, our results indicate that main scattering mechanism in samples with linear behavior of σ∝n comes from the Coulomb charged impurities. While the sub-linear behavior in other samples may result from the above three scattering mechanisms.