Effects of charged impurity scattering and substrate on the magneto-optical absorption properties in gapped monolayer graphene

Motivated by some earlier experimental observations on the magneto-optical absorption and cyclotron resonance in graphene, we carry out systematically a theoretical investigation of the magneto-optical absorption in graphene monolayer situated on a substrate. The effect of electron-impurity scattering is considered at low temperatures. The magneto-optical absorption coefficient (AC) is calculated using the perturbation theory taking account of both one- and two-photon absorption processes. Numerical results are obtained for the SiO₂, SiC, and h-BN substrates to compare and show effects of the substrate. There appear the cyclotron-impurity resonance peaks in the AC which show a blue-shift with increasing magnetic field strength. In general, the absorption intensity, the resonance energy and the FWHM depend strongly on the substrate. Also, the FWHM increases with increasing the impurity density by the law FWHM = β√{n_i } , where β is a constant whose value is different in different substrates and n_i the impurity density. In particular, the resonance energy versus magnetic field strength and the full width at half maximum (FWHM) for the SiO₂ substrate are in good agreement with those obtained by earlier experiments.