Optimized effective potentials from the random-phase approximation: Accuracy of the quasiparticle approximation

The optimized effective potential (OEP) method presents an unambiguous way to construct the Kohn–Sham corresponding a given diagrammatic approximation for exchange-correlation functional. OEP from random-phase (RPA) has played important role ever since conception of formalism. However, solution equation is computationally fairly expensive and be done in self-consistent way. So far, large scale solid state applications have, therefore, been performed only using quasiparticle (QPA), neglecting certain dynamical screening effects. We obtain exact RPA-OEP 15 semiconductors insulators by direct linearized Sham–Schlüter equation. investigate accuracy QPA on bandgaps dielectric constants, comment issue self-consistency.