SKM 2023 – wissenschaftliches Programm
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 6: Poster
KFM 6.5: Poster
Dienstag, 28. März 2023, 17:00–19:00, P3
Hybrid Functionals for Periodic Systems in the Density Functional Tight-Binding Method — •Tammo van der Heide1, Bálint Aradi1, Benjamin Hourahine2, Thomas Frauenheim1, and Thomas Niehaus3 — 1BCCMS, Univ. of Bremen, Bremen, Germany — 2SUPA, Dep. of Physics, The Univ. of Strathclyde, Glasgow, G4 0NG, UK — 3Institut Lumière Matière, Univ. Lyon, Univ. Claude Bernard Lyon 1, CNRS, Villeurbanne, France
Screened range-separated hybrid (SRSH) functionals within generalized Kohn-Sham density functional theory (GKS-DFT) have been shown to restore the correct 1/(rє) asymptotic decay of the screened Coulomb interaction in a dielectric environment (є). Major achievements of SRSH include an improved description of optical properties and correct prediction of polarization-induced fundamental gap renormalization in molecular crystals. The density functional tight-binding method (DFTB) is an approximate DFT that bridges the gap between first principles methods and empirical schemes. While RSH have already been accessible for molecular systems, effort has been made to generalize the theoretical foundation to extended systems beyond the Γ-point. For treating the periodic Fock exchange and its integrable singularity in reciprocal space, we resort to techniques successfully employed by DFT. Starting from the first principles Fock operator, we derive suitable expressions for the DFTB method, using standard integral approximations and their efficient implementation in the DFTB+ software package. Convergence behavior is investigated and demonstrated for the infinite acene series as well as 2D and 3D materials.