Reproducibility in $G_0W_0$ calculations for solids

Tonatiuh Rangel (1, 2) , Mauro del Ben (1) , Daniele Varsano (3, 4) , Gabriel Antonius (2, 1) , Fabien Bruneval (5, 1, 2) , Felipe H. da Jornada (1, 2) , Michiel J. van Setten (6, 4, 7) , Okan K. Orhan (8) , David D. O'Regan (8) , Andrew Canning (9) , Andrea Ferretti (10) , Andrea Marini (4, 11) , Gian-Marco Rignanese (6) , Jack Deslippe (12) , Steven G. Louie (1) , Jeffrey B. Neaton (1)

1 LBNL - Lawrence Berkeley National Laboratory [Berkeley]
2 Department of Physics, University of California
3 CNR NANO - Istituto Nanoscienze [Modena]
4 ETSF - European Theoretical Spectroscopy Facility
5 SRMP - Service de recherches de métallurgie physique
6 IMCN - Institut de la matière condensée et des nanosciences / Institute of Condensed Matter and Nanosciences
7 IMEC - IMEC
8 School of Physics [TCD Dublin]
9 CRD - Computational Research Division [LBNL Berkeley]
10 Centro S3
11 CNR-ISM - Istituto di Struttura della Materia
12 NERSC - National Energy Research Scientific Computing Center

Ab initio many-body perturbation theory within the GW approximation is a Green’s function formalism widely used in the calculation of quasiparticle excitation energies of solids. In what has become an increasingly standard approach, Kohn-Sham eigenenergies, generated from a DFT calculation with a strategically-chosen exchange correlation functional “starting point”, are used to construct G and W , and then perturbatively corrected by the resultant GW self-energy. In practice, there are several ways to construct the GW self-energy, and these can lead to variations in predicted quasiparticle energies. For example, for ZnO and TiO 2 , reported GW fundamental gaps can vary by more than 1 eV. In this work, we address the convergence and key approximations in contemporary G 0 W 0 calculations, including frequency-integration schemes and the treatment of the Coulomb divergence in the exact-exchange term. We study several systems, and compare three different GW codes: BerkeleyGW, Abinit and Yambo. We demonstrate, for the first time, that the same quasiparticle energies for systems in the condensed phase can be obtained with different codes, and we provide a comprehensive assessment of implementations of the GW approximation.

Domaines: Science des matériaux [cond-mat.mtrl-sci]; Physique Numérique [physics.comp-ph]

Tonatiuh Rangel, Mauro del Ben, Daniele Varsano, Gabriel Antonius, Fabien Bruneval, et al.. Reproducibility in $G_0W_0$ calculations for solids. Computer Physics Communications, 2020, 255, pp.107242. ⟨10.1016/j.cpc.2020.107242⟩. ⟨cea-02927610⟩