Revisiting the neutral C-vacancy in diamond: Localization of electrons through DFT plus U

Danny E. P. Vanpoucke*, Ken Haenen

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

8 Citations (Web of Science)

Abstract

The neutral C-vacancy is investigated using density functional theory calculations. We show that local functionals, such as PBE, can predict the correct stability order of the different spin states, and that the success of this prediction is related to the accurate description of the local magnetic configuration. Despite the correct prediction of the stability order, the PBE functional still fails predicting the defect states correctly. Introduction of a fraction of exact exchange, as is done in hybrid functionals such as HSE06, remedies this failure, but at a steep computational cost. Since the defect states are strongly localized, the introduction of additional on-site Coulomb and exchange interactions, through the DFT +U method, is shown to resolve the failure as well, but at a much lower computational cost. In this work, we present optimized U and J parameters for DFT+U calculations, allowing for the accurate prediction of defect states in defective diamond. The transferability of the U and J parameters is tested through the study of the split-interstitial.

Original languageEnglish
Pages (from-to)60-69
Number of pages10
JournalDiamond and Related Materials
Volume79
DOIs
Publication statusPublished - Oct 2017
Externally publishedYes

Keywords

  • Diamond
  • DFT
  • Defect
  • Electronic structure
  • RAMAN-SPECTROSCOPIC FEATURES
  • DENSITY-FUNCTIONAL THEORY
  • INTERSTITIAL DEFECT
  • SELF-DIFFUSION
  • SEMICONDUCTORS
  • NITROGEN

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