Dresden 2009 – wissenschaftliches Programm
O 21.1: Vortrag
Dienstag, 24. März 2009, 10:30–10:45, SCH A316
Embedding based order-N implementation of the FLAPW method — •Frank Freimuth1,2, Daniel Wortmann1,2, and Stefan Blügel1,2 — 1Institut für Festkörperforschung, Forschungszentrum Jülich, 52425 Jülich, Germany — 2Institute for Advanced Simulation, Forschungszentrum Jülich, 52425 Jülich, Germany
The Full-potential Linearized Augmented Plane Wave (FLAPW) method is known to set the standard for precision among the ab initio density functional theory codes. On the other hand, the computational effort of the FLAPW method is high and increases cubically with system size, making the applicability to large systems difficult.
In this talk we will discuss a Green-function (GF) based implementation of the FLAPW method suitable for the calculation of thick layered systems. Using the embedding method the layers may be calculated individually and joined together subsequently. The overall computational cost increases linearly with the number of layers. Our order-N GF implementation of the FLAPW method is able to fully replace the standard Bloch-function based implementation of the FLAPW method. Furthermore, the embedding concept allows to extend the applicability of the FLAPW framework to non-periodic infinite systems, e.g. surfaces and interfaces. Due to the high flexibility of the GF method general boundary conditions are easily imposed, e.g. the non-equilibrium situation arising in tunnel junctions under finite bias.
Besides the theoretical description of the method we give prove of evidence by presenting a set of applications for film, surface and transport calculations.