Regensburg 2013 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 64: Focus Session: Frontiers of electronic structure theory V (O, joinly with HL, TT)
HL 64.10: Vortrag
Mittwoch, 13. März 2013, 18:30–18:45, H36
Self-Consistent Density Functional Including Long-Range van der Waals Interactions — •Nicola Ferri1, Robert A. Distasio JR.2, Roberto Car2, Matthias Scheffler1, and Alexandre Tkatchenko1 — 1Fritz-Haber-Institut der MPG, Berlin, Germany — 2Princeton University, USA
Van der Waals (vdW) interactions are significant for a wide variety of systems, from noble-gas dimers to complex organic/inorganic interfaces. The long-range vdW energy is a tiny fraction (∼0.001%) of the total energy, hence it is typically assumed that vdW interactions do not change electronic properties. Although the vdW-DF functional self-consistently includes the effect of the vdW energy on electronic structure [1], the influence of “true” long-range vdW interactions is difficult to assess since a significant part of vdW-DF energy arises from short distances. Here, we present a self-consistent implementation of the long-range Tkatchenko-Scheffler (TS) density functional [2], including its extension to surfaces [3]. The analysis of self-consistency for rare-gas dimers allows us to reconcile two different views on vdW interactions: (i) Feynman’s view that advocates changes in the electron density, and (ii) atoms separated by an infinite barrier. In agreement with previous work [1], we find the contribution from self-consistency to be negligible in the structure and stability of vdW-bound complexes. However, a closer look at complex organic/inorganic interfaces reveals notable modification of the energy levels when using the self-consistent TS vdW density functional. [1] Thonhauser et al., PRB (2007), [2] Tkatchenko and Scheffler, PRL (2009), [3] Ruiz et al., PRL (2012).