Berlin 2015 – scientific programme

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O: Fachverband Oberflächenphysik

O 56: Frontiers of Electronic Structure Theory: Many-Body Effects on the Nano-Scale IV

O 56.4: Talk

Wednesday, March 18, 2015, 16:00–16:15, MA 004

A hybrid QM/EMT approach to charge state corrections — •Osman Baris Malcioglu¹ and Michel Bockstedte² — ¹Lst.f.Theor.Festkörperphysik, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany — ²FB Materialwissenschaften & Physik Universität Salzburg, 5020 Salzburg, Austria

Localized charge at surfaces, interfaces, or in volume materials naturally occur due to the ionization of adsorbates or defects. A robust quantitative description of charged systems is a prerequisite to explore the physics of adsorbates, surface and bulk defects of materials such as metal oxides. The popular supercell approach requires charge neutrality per supercell. For charged systems this is enforced by compensation charges. The resulting spurious interaction can be corrected a-posteriori [1,2]. Recently, a scheme based on model fitting the localized charge and dielectric screening was proposed [1]. Here, we present a fully automated and efficient hybrid QM/EMT approach for handling long-reach fields. The response of the medium and the localized charge density of the ab-initio calculations are represented by a finite element function space. The relevant physical observables are obtained using an auto-adaptive mesh solver. We demonstrate applications of our approach to charge state corrections of surface and bulk defects slabs in comparison with the earlier approaches [1,2].
¹ H.-P. Komsa and A. Pasquarello, Phys. Rev. Lett. 110, 095505 (2013).
² C. Freysoldt, J. Neugebauer, and C. G. Van de Walle, Phys. Rev. Lett. 102, 016402 (2009).