Regensburg 2019 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 74: Focus Session: Growth, Properties and Application of Epitaxial Graphene (joint session DS/HL/O)
O 74.6: Hauptvortrag
Donnerstag, 4. April 2019, 11:15–11:45, H32
Patternable non-polar epigraphene for nanoelectronics and Dirac point physics — Vladimir Prudkovskiy1, 3, Yiran Hu1, Hue Hu1, Lei Ma2, Claire Berger1,3, and •Walt de Heer1,2 — 1Georgia Institute of Technology, Atlanta USA — 2TICNN, Tianjin China — 3Neel Institute, CNRS, Grenoble, France
Recently reported measurements of epitaxial graphene nanoribbons grown on sidewalls etched in the 0001 face of h-SiC, Nature,506, 349, (2014) indicate that both spin and valley degeneracies are lifted, resulting in the observed 10 micron scale, temperature independent, single channel transport. These highly unusual properties were further investigated in SiC wavers that were cut at an angle to the 0001 face were prepared at the Tianjin International Center for Nanoparticles and Nanostructures. The wafers were graphitized and 10 micron scale top gated Hall bar structures were patterned using standard lithography methods. Magnetotransport measurements revealed striking transport properties. Single channel ballistic transport is observed even at the Dirac point. Moreover, an anomalous quantum Hall plateau is observed. Its anomalous value is caused by a quantized current that does not have a Hall effect, and that is in parallel with an equal current that does have a Hall effect. These properties are likely to be caused by edge currents, with energies that are pinned at the Dirac point. The ballistic transport is essentially temperature independent and consistent with that observed in sidewall ribbons. These results indicate that nonpolar epigraphene is a promising candidate for epigraphene nanoelectonics and important for Dirac point physics.