Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 22: Theoretical methods
O 22.5: Vortrag
Montag, 14. März 2011, 18:15–18:30, WIL C107
Tight-Binding Parameters from DFT Calculations: First Applications to Hydrocarbons — •Alexander Urban1, Martin Reese2, 3, Matous Mrovec2, 3, Christian Elsässer2, 3, and Bernd Meyer1 — 1ICMM/CCC, University of Erlangen-Nürnberg, Germany — 2Fraunhofer IWM, Freiburg, Germany — 3IZBS, Karlruhe Institute of Technology, Germany
Tight-binding (TB) models for practical calculations are usually derived by fitting band structures and total energies to results of DFT calculations or experimental data. We have developed an alternative approach in which the TB parameters are determined directly from DFT data for arbitrary reference configurations without extensive fitting. Our method [1] is conceptually different from previous approaches [2] as it is based on a projection [3] of basis-set-converged wave functions from mixed-basis DFT computations onto a minimal basis of atomic orbitals. The radial shape of the atomic orbitals is optimized by minimizing the loss (spillage) in the projection procedure. The Slater-Koster tables are then calculated with the optimized minimal basis using the self-consistent DFT Hamiltonian. To demonstrate the quality of the derived TB models results for the electronic structures, total energies and forces for different carbon and hydrocarbon systems will be compared to DFT reference data.
[1] A. Urban, M. Reese, M. Mrovec, C. Elsässer, B. Meyer, submitted
[2] D. Porezag et al., Phys. Rev. B 51 (1995) 12947
[3] D. Sanchez-Portal et al., Sol. State Comm. 95 (1995) 685