SKM 2023 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 67: Poster: Electronic Structure of Surfaces
O 67.10: Poster
Mittwoch, 29. März 2023, 18:00–20:00, P2/EG
Improved convergence of the density response function by an incomplete-basis correction — •Jörn Stöhler1,2, Markus Betzinger1, Stefan Blügel1, and Christoph Friedrich1 — 1Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich, Germany — 2RWTH Aachen University, Germany
The polarizability (or density response function) is a central quantity in many electronic structure methods, e.g., the GW approach, the random-phase-approximation (RPA) total-energy method, the optimized effective potential method, the Bethe-Salpeter approach, Coulomb-hole screened-exchange (COHSEX). In time-dependent perturbation theory, the polarizability can be expressed as a sum over unoccupied states. However, the resulting sum-over-states expression converges very slowly with respect to the number of bands or the basis-set size, in particular, in systems containing localized d- and f-states. Here, we discuss a method, called incomplete-basis-set correction [1,2], which augments the sum-over-states expression with a numerical solution of the radial Sternheimer equation in the atomic (muffin-tin) spheres. The method is implemented in the Spex code within the FLAPW approach. The resulting polarizability shows a considerably improved convergence behavior with respect to the basis set and the number of unoccupied states.
[1] M. Betzinger, C. Friedrich, A. Görling, S. Blügel, Phys. Rev. B 85, 245124 (2012), ibid. Phys. Rev. B 92, 245101 (2015).
[2] M. Betzinger, C. Friedrich, S. Blügel, PRB 88, 075130 (2013).