Dresden 2011 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 25: Topical Session Electron Theory II

MM 25.3: Talk

Wednesday, March 16, 2011, 15:15–15:30, IFW A

Charge transfer and localization within a tight binding framework — •Georg K. H. Madsen, Eunan J. McEniry, Nick Hatcher, and Ralf Drautz — ICAMS, Ruhr-Universität Bochum, Stiepeler Strasse 129, 44801 Bochum, Germany

The computational cost of density functional theory (DFT) places limitations on its application to both extended defects and to sampling the configuration space of complex phases. While these problems can be treated by empirical potentials, these can be questioned both from a view of transferability and physical justification.

From a computational point of view and from the wish to gain physical insight, one successful intermediate method between DFT and empirical potentials is the tight-binding (TB) method. In its conventional form the TB method models the total energy as a repulsive pair potential and a bonding many-body term. Using a down-folding technique we demonstrate how TB parameterizations can be constructed which involve a minimum number of fitting parameters and are based as closely as possible on the DFT energy functional.

We will discuss transition metal oxides and long range charge transfer within a tight binding framework based on the second order expansion of the DFT energy functional.