Berlin 2018 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 47: Theory of electronic structure
HL 47.5: Vortrag
Donnerstag, 15. März 2018, 17:15–17:30, EW 202
Excitonic optical spectra from a GW-free Bethe-Salpeter Equation — •Joshua Elliott1,2, Nicola Colonna3, Margherita Marsili1, Nicola Marzari3, and Paolo Umari1 — 1Dipartimento di Fisica e Astronomia, Università degli studi di Padova, Padova Italy — 2CNR-IOM DEMOCRITOS, Consiglio Nazionale delle Ricerche–Istituto Officina dei Materiali, c/o SISSA, Trieste, Italy — 3Theory and Simulation of Materials (THEOS) and National Centre for Computational Design and Discovery of Novel Materials (MARVEL), École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
We present our recent implementation that combines Koopman’s compliant (KC) Density Functionals with the Bethe-Salpeter Equation (BSE). Our method may be used to compute the optical properties of materials including excitonic effects, avoiding the costly GW-approximation. In this proof-of-concept work, quasiparticle eigenvalues are obtained perturbatively from the KC functional. Thus we use as input for the BSE: Kohn-Sham wavefunctions with quasiparticle-corrected energies, roughly equivalent to one-shot G0W0+BSE calculations. In addition, within the BSE calculation, we introduce a new method for obtaining the exact screened Coulomb interaction directly. This new approach has multiple advantages: it removes the need to compute the screened Coulomb interaction matrix, W(r,r′), further driving down the overall computation time and reducing the number of user-defined parameters. We evaluate the performance of our current implementation in the context of Thiel’s set, a collection of 28 organic molecules.