Stochastic GW with the Orthogonalized Projector Augmented Wave Method

Abstract

We introduce stochastic GW with the orthogonalized projector augmented-wave method (OPAW-sGW). This implementation enables accurate quasiparticle band gaps on significantly coarser real-space grids than norm-conserving pseudopotential sGW (NCPP-sGW). The orthogonalized PAW representation preserves the formal all-electron character and enables stochastic sampling of the Green's function and screened Coulomb interaction.

Figures (4)

• Figure 1: sGW and $\bar{\Delta}GW_0$ QP band gap comparison for naphthalene at varied grid spacings between NCPP and OPAW.
• Figure 2: NCPP and OPAW HOMO self-energy plots at varied grid spacings for naphthalene. The self-energy is evaluated at the difference between a specific energy and the quasiparticle (QP) energy of the HOMO ($\varepsilon_{\mathrm{HOMO}}$) at the corresponding level of theory and grid spacing.
• Figure 3: Molecular systems studied in this work.
• Figure 4: HOMO self-energy $\Sigma(\omega)$ calculated for Hexacene, $\mathrm{C}_{60}$, Kekulene, Chla, $10\text{-CPP}+\mathrm{C}_{60}$, and $\mathrm{C}_{96}\mathrm{H}_{24}$. The grid spacings used for the NCPP and OPAW calculations are listed in Tables I and II.The self-energy is evaluated at the difference between a specific energy and the quasiparticle (QP) energy of the HOMO ($\epsilon_{HOMO}$) at the corresponding level of theory, grid spacing, and molecular system.