Electronic confinement and coherence in patterned epitaxial graphene

Walt A. de Heer

Physics Department, Georgia Institute of Technology, Atlanta, USA

Utrathin epitaxial graphite was grown on single-crystal silicon carbide by vacuum graphitization. The material can be patterned using standard nanolithography methods. The transport properties, which are closely related to those of carbon nanotubes, are dominated by the single epitaxial graphene layer at the silicon carbide interface, and reveal the Dirac nature of the charge carriers. Patterned structures show quantum confinement of electrons and phase coherence lengths beyond one micrometer at 4K, with mobilities exceeding 2.5 m2/Vs. These parameters suggest that all-graphene electronically coherent devices may be possible. I will also discuss recent developments on unusual low-temperature phase transitions and fractal-like magnetoresistance effects that are occasionally observed in patterned graphene structures.