Berlin 2012 – scientific programme
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O: Fachverband Oberflächenphysik
O 29: Metal substrates: Adsorption of organic / bio molecules II
O 29.7: Talk
Tuesday, March 27, 2012, 12:00–12:15, MA 043
Assessing Density-Functional Theory with Screened van der Waals Interactions (DFT+vdWsurf) for Model Hybrid Inorganic/Organic Systems — •Nicola Ferri, Matthias Scheffler, and Alexandre Tkatchenko — Theory Department, Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin, Germany
Hybrid inorganic/organic systems (HIOS) are widely investigated
for usage in a variety of devices, e.g., for opto-electronic applications.
The interface geometry plays a crucial role in HIOS, and its correct description is a
requisite for predicting electronic properties.
Here we study two model HIOS: diindenoperylene (DIP, C32H16) and C60 on coinage metal surfaces (Cu(111), Ag(111), and Au(111)).
These systems are used to test the recently developed PBE+vdWsurf approach,
which accurately treats hybridization and long-range Coulomb screening, and includes interface
polarization effects [1].
We show that for both systems (DIP and C60), the PBE+vdWsurf approach
yields average equilibrium adsorption positions in excellent agreement (about 0.1 Å)
with experimental data. In the case of DIP, measurements have been performed using
X-ray standing wave technique plus X-ray photoelectron spectroscopy (XSW+XPS) [2].
In the case of C60, STM and LEED results are available [3].
Finally, we assess the role of self-consistency of the vdW energy in
the DFT+vdWsurf method, by adding the potential due to
vdW energy to the DFT potential.
[1] V. G. Ruiz et al., submitted to Phys. Rev. Lett. (2011).
[2] C. Bürker et al., http://ftp.esrf.eu/pub/UserReports/43789_A.pdf.
[3] H.L. Li et al., Phys. Rev. Lett. 103, 056101 (2009).