Regensburg 2019 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 20: Poster Monday: Electronic Structure

O 20.9: Poster

Montag, 1. April 2019, 17:45–20:00, Poster F

Optimization of a numerical integration procedure for the Korringa-Kohn-Rostoker Green's function method — •Irina Heinz, Alexander Fabian, Philipp Risius, and Christian Heiliger — Institut für theoretische Physik, Justus-Liebig-Universität Gießen, Gießen

For the description of material properties an efficient calculation of the density of states and charge density is invaluable. We calculate these quantities based on density functional theory (DFT) within the framework of the Korringa-Kohn-Rostoker (KKR) Green's function method. This method requires integrating the Green's function within a certain energy interval. However, due to the strongly structured Green's function the numerical integration requires a lot of computational effort. Therefore, integration is typically performed in the complex energy plane.

In the present case, we consider a rectangular contour in the complex energy plane. The numerical effort required depends on the position along the contour, particularly the imaginary part of the complex energy. In order to obtain reasonable numerical accuracy in conjunction with affordable computational time, we thoroughly analyze the dependence of the integral on certain numerical parameters such as the density of the k-mesh in reciprocal space and the choice of the energy grid along the integration contour.