Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 28: Electronic Structure Theory: General I
O 28.4: Vortrag
Dienstag, 13. März 2018, 11:15–11:30, MA 141
On the Nature of Self-Consistency in Density Functional Theory — •Nick Woods1, Mike Payne1, and Phil Hasnip2 — 1Theory of Condensed Matter, University of Cambridge — 2Condensed Matter Physics, University of York
Density functional theory (DFT) within the Kohn-Sham (KS) framework is a popular method for predicting the electronic structure of materials. The self-consistent field (SCF) method is an iterative procedure used to obtain a particle density that solves KS DFT (a `self-consistent' particle density). Density mixing is a particular class of these methods which combines the particle densities of past iterations in such a way that drives each iterative density closer to solving KS DFT. We begin by discussing the various difficulties presented by solving KS DFT from the point of view of achieving self-consistency with density mixing. Then, we present a systematic study of various density mixing methods proposed in literature, which are examined by utilising a representative test suite of over twenty input systems. These example systems involve cases ranging from simple to nearly pathological. The purpose of this work is to highlight where and why certain schemes perform particularly well. Secondly, we discuss how model dielectrics can be used to accelerate and stabilise convergence of density mixing schemes, and propose a scheme whereby a density-dependent (inhomogeneous) model dielectric can be posited and used to assist convergence.