Real-Space Representation of the Quasiparticle Self-Consistent GW Self-Energy and its Application to Defect Calculations

Ozan Dernek, Dmitry Skachkov, Walter Lambrecht, Mark van Schilfgaarde

Research output: Contribution to journalArticlepeer-review

2 Scopus Citations


The quasiparticle self-consistent (QS) GW (G for Green's function, W for screened Coulomb interaction) approach incorporates the corrections of the quasiparticle energies from their Kohn-Sham density functional theory (DFT) eigenvalues by means of an energy-independent and Hermitian self-energy matrix usually given in the basis set of the DFT eigenstates. By expanding these into an atom-centered basis set (specifically here the linearized muffin-tin orbitals) a real space representation of the self-energy corrections becomes possible. We show that this representation is relatively short-ranged. This offers opportunities to construct the self-energy of a complex system from parts of the system by a cut-and-paste method. Specifically for a point defect, represented in a large supercell, the self-energy can be constructed from those of the host and a smaller defect-containing cell. The self-energy of the periodic host can be constructed simply from a GW calculation for the primitive cell. We show for the case of the AsGa in GaAs that the defect part can already be well represented by a minimal eight-atom cell and allows us to construct the self-energy for a 64-atom cell in good agreement with direct QSGW calculations for the large cell. Using this approach to an even larger 216-atom cell shows the defect band approaches an isolated defect level. The calculations also allow us to identify a second defect band which appears as a resonance near the conduction band minimum. The results on the extracted defect levels agree well with Green's function calculations for an isolated defect and with experimental data.

Original languageAmerican English
Article numberArticle No. 205136
Number of pages12
JournalPhysical Review B
Issue number20
StatePublished - 15 May 2022

Bibliographical note

Publisher Copyright:
© 2022 American Physical Society.

NREL Publication Number

  • NREL/JA-5F00-82164


  • density functional theory
  • DFT
  • GW
  • Kohn-Sham
  • QSGW
  • quasiparticle
  • self-consistent
  • self-energy


Dive into the research topics of 'Real-Space Representation of the Quasiparticle Self-Consistent GW Self-Energy and its Application to Defect Calculations'. Together they form a unique fingerprint.

Cite this