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O: Fachverband Oberflächenphysik

O 36: Poster Session II (Metals; Nanostructures at surfaces; Surface or interface magnetism; Spin-Orbit Interaction at Surfaces; Electron and spin dynamics; Surface dynamics; Methods; Theory and computation of electronic structure)

O 36.128: Poster

Dienstag, 15. März 2011, 18:30–22:00, P4

KKRnano, a code for accurate density functional calculations for systems with thousands of atoms — •Rudolf Zeller, Alexander Thiess, and Stefan Blügel — Peter-Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich und JARA, D-52425 Jülich

The present state of our newly developed computer code KKRnano will be outlined. The code, which is designed for massively parallel computing, is based on the Korringa-Kohn-Rostoker (KKR) Green function method and can be applied to supercells with arbitrary atomic arrangements. KKRnano uses an iterative solution of the algebraic Dyson equation which describes the interaction between otherwise independent single atomic scattering events. Because of that efficient parallelization and reduced scaling of the computational effort (quadratically instead of cubically with the number of atoms) are easily achieved. For large systems calculations with linear scaling effort are possible if small total energy errors are admitted (less than 1 meV per atom). In particular, it will be explained how a preconditioner for the iterative solution can be constructed so that the calculations are accelerated by about a factor ten for all systems investigated so far which include metallic systems, defect levels in Si, magnetic GaN:Gd with O and N codoping and GeSbTe phase-change materials.