Dresden 2014 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 55: Focussed Session: Towards a Quantitative Understanding of Complex Adsorption Structures: Surface Science goes Organic I

O 55.3: Vortrag

Mittwoch, 2. April 2014, 16:45–17:00, TRE Phy

Electronic Properties of Surfaces and Interfaces with Self-Consistent van der Waals Density Functional — •Nicola Ferri¹, Robert A. Distasio Jr.², Roberto Car², Alexandre Tkatchenko¹, and Matthias Scheffler¹ — ¹Fritz-Haber-Institut der MPG, Berlin, Germany — ²Princeton University, Princeton, NJ, USA

The long-range van der Waals (vdW) energy is a tiny part (0.001%) of the total energy, hence it is typically assumed to have a minor influence on the electronic properties. Here, we address this question through a fully self-consistent (SC) implementation of the long-range Tkatchenko-Scheffler (TS) density functional [1]. The effects of TS-vdW^SC on electron density differences for atomic and molecular dimers are compared with correlated densities obtained from “gold standard” coupled-cluster quantum-chemical calculations finding a qualitatively and quantitatively accordance. In agreement with previous work [2], we find a very small overall contribution from self-consistency in the structure and stability of vdW-bound molecular complexes. However, TS-vdW^SC (coupled with PBE functional) significantly affects electronic properties of coinage metal (111) surfaces, leading to an increase of up to 0.3 eV in the workfunction in agreement with experiments. Furthermore, vdW interactions visibly influence workfunctions in hybrid organic/metal interfaces, changing Pauli push-back and charge transfer contributions. [1] A. Tkatchenko and M. Scheffler, PRL (2009). [2] T. Thonhauser et al., PRB (2007).