Accurate Quasiparticle Spectra from Self-ConsistentGWCalculations with Vertex Corrections

Abstract

Self-consistent GW calculations, maintaining only the quasiparticle part of the Green's function G, are reported for a wide class of materials, including small gap semiconductors and large gap insulators. We show that the inclusion of the attractive electron-hole interaction via an effective nonlocal exchange correlation kernel is required to obtain accurate band gaps in the framework of self-consistent GW calculations. If these are accounted for via vertex corrections in W, the band gaps are found to be within a few percent of the experimental values.

Ab‐initio theory of semiconductor band structures: New developments and progress

“…The resulting macroscopic electronic dielectric constants are larger and agree better with experimental values, in turn reducing the QP gap. A reduction of the QP gap by about 0.17/0.12 eV (Si) and 0.60/0.52 eV (ZnO) [51,65] is observed. Hence, the gap overestimation for Si (Table 3, self-consistent) is significantly reduced, whereas the strong reduction for ZnO clearly worsens agreement with experiment.…”

“…The spin-orbit coupling may be crucial for p-and d-states of compounds with heavy elements such as PbS, PbSe, and PbTe, where it is of the order of 0.5 eV [51]. For other compounds, e.g.…”

Accurate energy bands calculated by the hybrid quasiparticle self-consistent GW method implemented in the ecalj package

“…2, this can be due to the too small screening effect in the RPA, which neglects electron-hole correlations in the appropriate polarization function [4], and/or the screening effect of phonons suggested by Botti and Marques [37]. Thus, it must be preferable to use the above-mentioned methods to remedy the overestimation from the view point of physics; however, these methods can be computationally very demanding.…”

Modelling materials for solar fuel synthesis by artificial photosynthesis; predicting the optical, electronic and redox properties of photocatalysts

“…BSE calculations are performed on top of Green's-function-based GW ionisation potential and electron affinity calculations [63,70,71], which are started from the eigenvalues and wavefunctions from a ground state DFT calculation. While self-consistent GW calculations are possible [72][73][74][75][76], most BSE calculations are performed on top of non self-consistent G 0 W 0 or partially self-consistent GW 0 calculations and hence will show some dependence on the XC functional used in the underlying DFT calculation. GW calculation also requires testing for convergence in terms of the number of empty states to include, and the method and quality of frequency integration.…”