Optimally tuned starting point for single-shotGWcalculations of solids

Abstract

The dependence of ab initio many-body perturbation theory within the GW approximation on the eigensystem used in calculating quasiparticle corrections limits this method's predictive power. Here, we investigate the accuracy of the recently developed Wannier-localized optimally tuned screened range-separated hybrid (WOT-SRSH) functional as a generalized Kohn-Sham starting point for single-shot GW (G 0 W 0 ) calculations for a range of semiconductors and insulators. Comparison to calculations based on well-established functionals, namely, PBE, PBE0, and HSE, as well as to self-consistent GW schemes and to experiment, shows that band gaps computed via G 0 W 0 @WOT-SRSH have a level of precision and accuracy that is comparable to that of more advanced methods such as quasiparticle self-consistent GW and eigenvalue self-consistent GW . We also find that G 0 W 0 @WOT-SRSH improves the description of states deeper in the valence band manifold. Finally, we show that G 0 W 0 @WOT-SRSH significantly reduces the sensitivity of computed band gaps to ambiguities in the underlying WOT-SRSH tuning procedure.

Band gaps of halide perovskites from a Wannier-localized optimally tuned screened range-separated hybrid functional

“…However, the reduced effective mass is in good agreement with experimental measurements. A smaller effective mass is an indication of wider bandwidth, in line with previous comparisons of SRSH and GW bandwidths [62,63].…”

“…m * e , m * h , and μ are the electron, hole, and reduced effective masses, respectively, where μ bands (each of which allows for spin-orbit splitting) the mean absolute deviation is 0.08 eV and the largest deviation is 0.18 eV. These deviations are small and in line with previous comparisons of SRSH and GW band structures [62,63].…”

Accurate and Efficient Computation of the Fundamental Bandgap of the Vacancy-Ordered Double Perovskite Cs2TiBr6

“…the use of a HSE06 functional starting point decreased the single-shot MAE from 0.40 eV for PBE to 0.22 eV. 136 This is comparable with the evGW 0 @PBE MAE of 0.24 eV for 23 solids. 49 On this basis of these MAEs the G 0 W 0 @HSE06 values of ref 28 also agree closely with the present work.…”

First-Principles Studies of the Electronic and Optical Properties of Zinc Titanium Nitride: The Role of Cation Disorder

“…The so-called range separation parameter, which dictates the length scale at which the Coulomb potential transitions from its short-range form to its long-range form, is tuned to satisfy an ionization potential (IP) ansatz; at long range, the fraction of exact exchange is set by the averaged high-frequency dielectric constant, here 6.81. WOT-SRSH has been shown to predict the fundamental band gap accurately for standard semiconductors, metal oxides, and halide perovskites, and it has been shown to be an optimal starting point for one-shot GW calculations . Using α = 0.25 (the fraction of exact exchange in short range) and α + β = 0.147 (the fraction of exact exchange in long range, determined by 1 ϵ ∞ ), we determine that a range separation parameter of γ = 1.07 Bohr –1 satisfies the IP ansatz for cation-ordered ZnTiN 2 , following the procedure outlined in prior work (see Supporting Information for details).…”