Riemelmoser Stefan, Kaltak Merzuk, Kresse Georg
Faculty of Physics and Center for Computational Materials Science, University of Vienna, Kolingasse 14-16, A-1090 Vienna, Austria.
VASP Software GmbH, Sensengasse 8/17, A-1090 Vienna, Austria.
J Chem Phys. 2021 Apr 21;154(15):154103. doi: 10.1063/5.0045400.
The optimized effective potential (OEP) method presents an unambiguous way to construct the Kohn-Sham potential corresponding to a given diagrammatic approximation for the exchange-correlation functional. The OEP from the random-phase approximation (RPA) has played an important role ever since the conception of the OEP formalism. However, the solution of the OEP equation is computationally fairly expensive and has to be done in a self-consistent way. So far, large scale solid state applications have, therefore, been performed only using the quasiparticle approximation (QPA), neglecting certain dynamical screening effects. We obtain the exact RPA-OEP for 15 semiconductors and insulators by direct solution of the linearized Sham-Schlüter equation. We investigate the accuracy of the QPA on Kohn-Sham bandgaps and dielectric constants, and comment on the issue of self-consistency.
优化有效势（OEP）方法为构建与给定交换关联泛函的图解近似相对应的科恩-沈势提供了一种明确的方法。自OEP形式主义提出以来，随机相位近似（RPA）的OEP就发挥了重要作用。然而，OEP方程的求解在计算上相当昂贵，并且必须以自洽的方式进行。因此，到目前为止，大规模固态应用仅使用准粒子近似（QPA）来进行，而忽略了某些动态屏蔽效应。我们通过直接求解线性化的沈-施吕特方程，得到了15种半导体和绝缘体的精确RPA-OEP。我们研究了QPA在科恩-沈带隙和介电常数方面的准确性，并对自洽性问题进行了评论。
