Berlin 2015 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 21: Graphene: Growth & Intercalation
O 21.1: Vortrag
Dienstag, 17. März 2015, 10:30–10:45, MA 041
First-principles Study of the Origin of a Rippled Graphene Phase on Ir(001) — •Mighfar Imam1, Natasa Stojic1,2, and Nadia Binggeli1,2 — 1The Abdus Salam International Centre for Theoretical Physics Strada Costiera 11, 34151 Trieste, Italy — 2IOM-CNR Democritos, Trieste, I-34151, Italy
An interesting graphene phase on Ir(001) comprising ordered one-dimensional ripples of nanometer periodicity with exceptionally large buckling has recently been observed experimentally [1]. In this phase, chemisorbed lines of graphene, only a few nanometers wide, strongly bind to the substrate along Ir[010], while the whole graphene film markedly buckles between these periodic lines, resulting in graphene ripples along Ir[100]. We have performed a density functional theory study including the long range van der Waals interactions to investigate the microscopic mechanisms responsible for the formation of this new graphene phase on Ir(001). With our calculated trends of the chemisorption and rippling energies, we explain the appearance of a buckled chemisorbed phase with a specific nanometer periodicity. We have also analyzed the effect of changing graphene curvature on its electronic structure and chemisorption energy, finding a new feature in the conduction band close to the Fermi energy. This new feature in the conduction states is identified as the one largely responsible for the strong local chemisorption of graphene.
[1] A. Locatelli et al., ACS Nano, 7, 6955 (2013)