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O: Fachverband Oberflächenphysik
O 33: Methods: Electronic structure theory II
O 33.1: Vortrag
Mittwoch, 25. März 2009, 10:30–10:45, SCH A316
Exploring the Interaction between Graphene Sheets: a Local xc Correction Study — •Andrea Sanfilippo1, Xinguo Ren1, Patrick Rinke1,2, Alexander Tkatchenko1, Volker Blum1, Matthias Scheffler1,2, and Karsten Reuter1 — 1Fritz-Haber-Institut, D-14195 Berlin (Germany) — 2UC Santa Barbara, CA 93106 (USA)
The interaction between two graphene sheets has become an important test case when assessing the performance of approximate treatments of electronic exchange and correlation (xc) in the context of van der Waals interactions. Of interest is not only the interaction strength at equilibrium separation, but also the long-range asymptotic behavior, which is expected to be influenced by the half-metallic nature of the graphene band structure. Practical work in this direction is hitherto hampered by existing limitations in applying more sophisticated xc approaches, like correlated wave function techniques, to extended systems. We demonstrate how this can be overcome using a local xc correction formalism [1], which enables an accurate extrapolation of energetics and forces obtained from small cluster calculations. We illustrate this using hybrid functionals, MP2 and the random phase approximation, and compare the obtained ab initio results [2] to analytical predictions for the asymptotic behavior of the electrostatic and dispersive interactions. [1] Q.M. Hu, K. Reuter, and M. Scheffler, Phys. Rev. Lett. 98, 176103 (2007). [2] V. Blum et al., Comp. Phys. Commun. (in press).