Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 98: Graphene VI

O 98.3: Vortrag

Freitag, 18. März 2011, 11:45–12:00, WIL A317

Accurate adsorption energies of graphene/Ni(111) — •Florian Mittendorfer — TU Vienna, Vienna, Austria

Due to the exceptional transport properties of graphene, graphene-based materials offer a promising route for spintronics. Yet even a prototypical system for a spin-filtering device, the interface between a ferromagnetic surface and a graphene sheet, cannot be described consistently on the basis of density functional theory (DFT) calculations. Even advanced functionals, such as the van der Waals density functional (vdW-DF), vastly overestimate the metal-graphene distance for graphene/Ni(111) [1], and hence fail to predict the experimentally observed opening of a band gap at the Dirac point.

In a recent publication, we could demonstrate that the description of adsorption energies can be significantly improved using a many-electron approach, the random phase approximation (RPA) [2]. In this contribution, we present RPA calculations for the adsorption of graphene on Ni(111). Using this approach, we could not only predict the correct adsorption site and electronic structure of the adsorbed graphene, but also determine the adsorption energy of the system accurately. The RPA calculations allow to evaluate the non-local (van der Waals) contributions and consequently to assess the quality of computationally cheaper approaches.

[1] M. Vanin, J. J. Mortensen, A. K. Kelkkanen, et al., Phys. Rev. B 81, 081408(R) (2010)

[2] L. Schimka, J. Harl, A. Stroppa, et al., Nature Materials 9, 741 (2010)