Simple eigenvalue-self-consistent [Formula: see text]

Vojtěch Vlček; Roi Baer; Eran Rabani; Daniel Neuhauser

doi:10.1063/1.5042785

Simple eigenvalue-self-consistent $\bar{Δ} G W_{0}$

J Chem Phys. 2018 Nov 7;149(17):174107. doi: 10.1063/1.5042785.

Authors

Vojtěch Vlček¹, Roi Baer², Eran Rabani³, Daniel Neuhauser¹

Affiliations

¹ Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA.
² Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
³ Department of Chemistry, University of California and Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.

PMID: 30409020
DOI: 10.1063/1.5042785

Abstract

We show that a rigid scissors-like GW self-consistency approach, labeled here $\bar{Δ} G W_{0}$ , can be trivially implemented at zero additional cost for large scale one-shot G ₀ W ₀ calculations. The method significantly improves one-shot G ₀ W ₀ and for large systems is very accurate. $\bar{Δ} G W_{0}$ is similar in spirit to evGW ₀ where the self-consistency is only applied on the eigenvalues entering Green's function, while both W and the eigenvectors of Green's function are held fixed. $\bar{Δ} G W_{0}$ further assumes that the shift of the eigenvalues is rigid scissors-like so that all occupied states are shifted by the same amount and analogously for all the unoccupied states. We show that this results in a trivial modification of the time-dependent G ₀ W ₀ self-energy, enabling an a posteriori self-consistency cycle. The method is applicable for our recent stochastic-GW approach, thereby enabling self-consistent calculations for giant systems with thousands of electrons. The accuracy of $\bar{Δ} G W_{0}$ increases with the system size. For molecules, it is up to 0.4-0.5 eV away from coupled-cluster single double triple (CCSD(T)), but for tetracene and hexacene, it matches the ionization energies from both CCSD(T) and evGW ₀ to better than 0.05 eV. For solids, as exemplified here by periodic supercells of semiconductors and insulators with 6192 valence electrons, the method matches evGW ₀ quite well and both methods are in good agreement with the experiment.