Regensburg 2010 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 43: Electronic Structure and Atomistic Modeling

HL 43.1: Vortrag

Mittwoch, 24. März 2010, 14:00–14:15, H14

Does the KLI approximation work for current-density-functional theory? — •Marc Siegmund and Oleg Pankratov — Lehrstuhl für Theoretische Festkörperphysik, Universität Erlangen-Nürnberg, Staudtstr. 7/B2, 91058 Erlangen, Germany

Orbital exchange-correlation functionals which depend explicitly on the Kohn-Sham orbitals but only implicitly on the density became popular in the last years. These functionals systematically improve the description of many-body effects within density-functional theory. Among those, the optimized effective potential (OEP) method is often employed which expresses the exchange-correlation potential as a solution of complicated integral equations. Due to the complexity of these equations, a simplification known as the Krieger-Li-Iafrate (KLI) approximation is widely used in practice.

Recently, the OEP integral equations and the KLI approximation have been derived for current-density-functional theory (CDFT) [1]. Using a one-dimensional model system, we discuss the applicability of the KLI approximation in this case. A numerical example shows, that the solution of the CDFT-KLI equations may produce the exchange-correlation vector potential which leads to violation of the continuity equation. On the contrary, the solution of the full CDFT-OEP equations does not suffer from this shortcoming.

[1] S. Pittalis, S. Kurth, N. Helbig, and E.K.U. Gross, Physical Review A 74, 062511 (2006)