SKM 2021 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 18: Posters Magnetism V

MA 18.31: Poster

Freitag, 1. Oktober 2021, 10:00–13:00, P

An automated tool for generation of optimal Voronoi tessellation of crystal structures by the inclusion of void sites — •Roman Kováčik and Stefan Blügel — Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany

The performance of the electronic structure calculation within the Korringa-Kohn-Rostoker Green function method strongly relies on a good convergence with respect to the angular momentum expansion. This in turn depends on an as close-packed as possible definition of the atomic structure, due to the Voronoi tessellation used to partition the space. Hence, for the crystal structures with low packing density, an appropriate set of void sites has to be defined, which we address in our newly developed python tool.

The lower and upper bound of the number of void sites is estimated from the packing density, using simple geometrical arguments or assuming atomic radii of the present species. Within these bounds, a number of all distinct sets of Wyckoff positions is generated, corresponding to the space group of the input structure and yet unoccupied by present atoms. In case of a free coordinate in a particular Wyckoff position, a user defined number of random initial positions are tried. The fitness of the resulting Voronoi tessellation is examined as a function of the radius of void sites from the minimum ratio of inscribed and circumscribed sphere and the maximum ratio of circumscribed sphere and nearest neighbor distance over the Voronoi cells. Solutions are presented for several trivial and non-trivial crystal structures.