AVS 54th International Symposium | |
Thin Film | Tuesday Sessions |
Session TF-TuM |
Session: | Two-Dimensional Carbon Nanostructures |
Presenter: | G.M. Rutter, Georgia Institute of Technology |
Authors: | G.M. Rutter, Georgia Institute of Technology J.N. Crain, National Institute of Standards and Technology N.P. Guisinger, National Institute of Standards and Technology P.N. First, Georgia Institute of Technology J.A. Stroscio, National Institute of Standards and Technology |
Correspondent: | Click to Email |
Understanding the role that defects play in the transport properties of graphene is essential for realizing potential carbon-based electronics. In this study, scanning tunneling spectroscopy was used to measure scattering from defects in epitaxial graphene grown on SiC(0001). Energy-resolved maps of the differential conductance reveal standing-wave modulations of the local density of states on two different length scales, corresponding to two classes of allowed scattering vectors. While backscattering is normally suppressed due to the chiral symmetry of Dirac quasiparticles in graphene, the presence of atomic defects is shown to mix quasiparticle wavefunctions of different symmetries. From Fourier transforms of the spectroscopic conductance maps we determine the energy-momentum dispersion relation for both occupied and unoccupied states near the Fermi level of single-layer and bilayer epitaxial graphene. * This work was supported in part by the Office of Naval Research, by Intel Research, and by NSF grant ECS-0404084.