Schedule Nov 06, 2009
A Self-Consistent van der Waals Density Functional Study of Adsorption on Metal Surfaces
Marco Vanin (DTU)

M. Vanin1, A. Kelkkanen1, K. S. Thygesen1 B. I. Lundqvist1,2 K. W. Jacobsen1

  1. Center for Atomic-scale Materials Design (CAMD), Department of Physics, Technical University of Denmark,DK -2800 Kgs. Lyngby, Denmark.
  2. Department of Applied Physics, Chalmers University of Technology, SE ­41296 Göteborg, Sweden.

The van der Waals Density Functional (vdW-DF)1 has recently been implemented in the GPAW2 software, as recently proposed by Perez and Soler3 . This has made Self-Consistent vdW-DF calculations possible for systems such as benzene and graphene adsorption on various metal surfaces. A self-consistent vdW-DF cal­culation turns out to take around 80 percent more time than a self-consistent GGA calculation with roughly the same amount of density iterations. We have applied the vdW-DF functional to bulk metals and we have found that it sig­ni?cantly overestimates lattice parameters, in particular for transition and noble metals, compared to the revPBE results. This turns out not to be a problem re­lated to self-consistency but is believed to be due to the mix of LDA correlation and revPBE exchange in the vdW-DF. We have also analyzed the adsorption on graphene and benzene on di?erent (111) metal surfaces and we discuss the results in comparison with traditional LDA and GGA calculations.

1M Dion, H. Rydberg, E. Schröder, D.C Langreth and B.I Lundqvist, Phys. Rev. Lett. 92 246401 (2004)
2J. J. Mortensen, L. B Hansen, and K. W. Jacobsen, Phys. Rev. B 71, 035109 (2005)
3G.R. Perez, J.M Soler, Phys. Rev. Lett. 103 096102 (2009)

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