Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 107: Graphene: Electronic Structure (jointly with O, HL)
TT 107.10: Vortrag
Donnerstag, 19. März 2015, 17:15–17:30, MA 041
Structure and electronic states of the zig-zag graphene/h-BN interface — •Robert Drost1, Andreas Uppstu2, Kezilebieke Shawulienu1, Fabian Schulz1, Sampsa K. Hämäläinen1, Mikko Ervasti2, Ari Harju2, and Peter Liljeroth1 — 1Department of Applied Physics, Aalto University School of Science, Finland — 2COMP Centre of Excellence and Helsinki Institute of Physics, Department of Applied Physics, Aalto University School of Science, Finland
Some of the most exciting properties of graphene (G) are only realised in atomically precise nanostructures. The zig-zag (ZZ) edges of this two-dimensional crystal host localised states that have been proposed to be used in spin- and valleytronic applications: Using the spin degree of freedom of the electron or the valley degree of freedom of the honeycomb crystal structure to transmit and process information. While well studied theoretically, experimental realisations remain challenging. We passivate the ZZ edge of epitaxial G with hexagonal boron-nitride (BN), a 2D insulator isostructural to G, to preserve the edge state in the band gap of the insulator. We investigate the growth of atomically perfect G/BN heterostructures on Ir(111) and Ni(111) substrates and discuss the effect of varying substrate interaction. The intrinsic properties of the G/BN interface may be revealed by intercalation with gold. Using low-temperature STM, we demonstrate the existence of a localised electronic state on the ZZ oriented G/BN interfaces. Tight binding and DFT calculations show that the interface retains many important properties of the graphene edge state.