Berlin 2012 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 55: Theoretical methods II

O 55.7: Vortrag

Mittwoch, 28. März 2012, 18:15–18:30, MA 043

The Role of van der Waals Interactions for Non-Metallic Solids — •Guo-Xu Zhang, Alexandre Tkatchenko, and Matthias Scheffler — Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin, Germany

Cohesion in non-metallic solids arises mainly from covalent bonding and/or electrostatic interactions, and it is typically assumed that van der Waals (vdW) forces play a minor role. Nevertheless, the qualitative and quantitative role of vdW interactions has been a matter of discussion for quite some time. In particular, most state-of-the-art functionals, based on the generalized gradient approximation (GGA), meta-GGA, or (screened) hybrid functionals yield systematic deviations for the lattice constants, cohesive energies, and bulk moduli for a wide range of solid-state systems. We recently demonstrated that vdW interactions play an important role for the quantitative description of cohesive properties of benchmark semiconductors and ionic solids [1]. Here we extend our study to a wide range of materials including ionic crystals, semiconductors, and insulators. The vdW energy is computed using our recently developed DFT+MBD method [2], which includes short- and long-range Coulomb screening effects, and computes the many-body vdW energy to infinite order in the dipole approximation. We show that many-body vdW interactions play a significant role for cohesive properties of non-metallic solids.

[1] G.-X. Zhang et al., Phys. Rev. Lett., in print (2011); [2] A. Tkatchenko, R. A. DiStasio Jr., R. Car, and M. Scheffler, submitted.