Berlin 2012 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 65: Graphene V
O 65.5: Vortrag
Donnerstag, 29. März 2012, 11:30–11:45, MA 041
DFT studies of Graphene on Ni(111) and Surface Nickel Carbide Ni2C — •Andreas Garhofer1, Peter Jacobsen1,2, Bernhard Stoeger1, Gareth S. Parkinson1, Michael Schmid1, Roman Caudillo3, Florian Mittendorfer1, Josef Redinger1, and Ulrike Diebold1,2 — 1Institute of Applied Physics, TU Wien, Austria — 2Tulane University, USA — 3Intel Corporation
Graphene with its unique transport properties supported on ferromagnetic materials is a promising candidate for the fabrication of spin-filtering devices. In order to study the growth of graphene on metal surfaces, graphene on Ni(111) is a perfect system from a structural point of view.
We studied the systems using the DFT program package VASP with the vdW-DF method in the flavor of optB88 to include van der Waals interactions. In our theoretical discussion we analyzed the growth of graphene and Ni2C on Ni(111). We calculated the stability of the surface carbide phase and the binding energies of rotated and unrotated graphene on Ni(111) as well as on Ni2C. Graphene and Ni2C have no epitaxial relationship due to their incommensurate lattices, leading to a spread in grain rotations. The CVD growth of graphene on Ni(111) was also studied with STM. The experiments showed not only perfect aligned (1x1) structures, but also several moiré patterns. They are due to grain rotations of graphene on both Ni(111) and also surface nickel carbide Ni2C. During CVD growth, carbon atoms segregate into the Ni bulk. With an increasing carbon concentration first the surface carbide and then a graphene layer on top is built.