Divacancy in 3C- and 4H-SiC: An extremely stable defect

Leena Torpo*, T.E.M. Staab, Risto Nieminen

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

56 Citations (Scopus)
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Using first-principles calculations for divacancy defects in 3 C- and 4H-SiC, we determine their formation energies and stability, their ionization levels, and relaxed geometries (symmetry point groups) for neutral as well as for charged states. For 4H-SiC all four possible nearest-neighbor divacancy configurations are considered. We find not only a remarkable high binding energy of about 4 eV, but also a strong site dependence (cubic or hexagonal lattice sites) of the formation energies. Applying a Madelung-type correction to deal with the electrostatic interactions between charged supercells, our results indicate a negative-U behavior at Ev + 0.7 eV between the charge states 1 +/1- only for nearest-neighbor divacancies on different lattice sites (mixed cubic and hexagonal) in 4H-SiC, but not for all the other cases (pure cubic or pure hexagonal) in 4H-or for the cubic divacancy in 3 C-SiC.

Original languageEnglish
Article number085202
Pages (from-to)1-10
JournalPhysical Review B
Issue number8
Publication statusPublished - 15 Feb 2002
MoE publication typeA1 Journal article-refereed

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