Regensburg 2013 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 88: Focus Session: Frontiers of electronic structure theory VII (O, jointly with HL, TT)

HL 88.9: Talk

Thursday, March 14, 2013, 18:00–18:15, H36

Generalized incomplete-basis-set correction applied to EXX-OEP — •Markus Betzinger, Christoph Friedrich, and Stefan Blügel — Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany

We recently derived [1] an incomplete-basis-set correction (IBC) for all-electron response functions within the full-potential linearized augmented plane-wave (FLAPW) method as realized in the FLEUR code [2]. The IBC utilizes the potential dependence of the LAPW basis functions whose response is calculated explicitly by solving radial Sternheimer equations in the spheres. While in the original formulation of the IBC [1] only spherical perturbations of the potential have been taken into account, we show here an extension to non-spherical perturbations, replacing the single radial Sternheimer equation for each angular momentum ℓ by a set of equations coupling different angular momenta. Likewise, the response of the core electrons is computed. We demonstrate that this generalized IBC improves further the convergence in terms of basis-set size and number of unoccupied states. We apply the generalized IBC to the exact-exchange (EXX) optimized-effective-potential (OEP) approach. While for simple semiconductors and insulators the original IBC already leads to a physical and stable local EXX potential, we show that for more complex materials like NiO, whose band gap is formed by d states, the generalization of the IBC is crucial to obtain a well-converged local optimized potential.
M. Betzinger et al., Phys. Rev. B 85, 245124 (2012)
http://www.flapw.de