Simple eigenvalue-self-consistent Δ ̄ G W 0

Vojtěch Vlček, Roi Baer, Eran Rabani, Daniel Neuhauser

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Abstract

We show that a rigid scissors-like GW self-consistency approach, labeled here Δ̄GW0, can be trivially implemented at zero additional cost for large scale one-shot G0W0 calculations. The method significantly improves one-shot G0W0 and for large systems is very accurate. Δ̄GW0 is similar in spirit to evGW0 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. Δ̄GW0 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 G0W0 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 Δ̄GW0 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 evGW0 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 evGW0 quite well and both methods are in good agreement with the experiment.

Original languageAmerican English
Article number174107
JournalJournal of Chemical Physics
Volume149
Issue number17
DOIs
StatePublished - 7 Nov 2018

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© 2018 Author(s).

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