Regensburg 2016 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 15: Poster session I

MM 15.1: Poster

Montag, 7. März 2016, 18:00–20:00, Poster B3

Forces in the KKR method — •Roman Kováčik, Rudolf Zeller, and Stefan Blügel — Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany

An accurate calculation of the ionic forces in the Korringa-Kohn-Rostoker Green function (KKR-GF) method is crucial for its applicability to large scale material science simulations. In turn, the calculation of forces relies on an accurate evaluation of the electrostatic potential, especially in the interstitial regions where the intersite terms exhibit very poor convergence with the angular momentum expansion. We explore and analyze an alternative method for the numerical solution of Poisson’s equation, based on a direct integration within space-filling Voronoi polyhedra [1]. An accurate and efficient isoparametric integration scheme without the use of shape functions is employed [2]. Furthermore, an alternative summation form is applied to the expressions in the Ewald procedure [3]. This approach is implemented and tested within the KKR-GF framework in the KKRnano computational code [4].

[1] A. Alam et al., Phys. Rev. B 84, 205106 (2011).
[2] A. Alam et al., Phys. Rev. B 84, 045105 (2011).
[3] R. Zeller, J. Phys.: Condens. Matter 27, 306301 (2015).
[4] A. Thiess et al., Phys. Rev. B 85, 235103 (2012).