Contribution of the buffer layer to the Raman spectrum of epitaxial graphene on SiC(0001)

3)R30 ◦ periodicity which forms the intrinsic interface structure between epitax-ial graphene and SiC(0001). We show that this interface structure leads to a non-vanishing signal in the Raman spectrum at frequencies in the range of the D- and G-band of graphene and discuss its shape and intensity. Ab-initio phonon calculations reveal that these features can be attributed to the vibrational density of states of the buffer-layer. PACS numbers: 63.22.Rc