Gallium self-interstitial relaxation in GaAs: An ab initio characterization

Marc André Malouin, Fadwa El-Mellouhi, Normand Mousseau

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Ga interstitials in GaAs (IGa) are studied using the local-orbital ab initio code SIESTA in a supercell of 216+1 atoms. Starting from eight different initial configurations, we find five metastable structures: the two tetrahedral sites in addition to the 110- split[Ga-As], 111- split[Ga-As], and 110- split[Ga-Ga]. Studying the competition between various configuration and charges of IGa at T=0 K, we find that predominant gallium interstitials in GaAs are charged +1, neutral, or at most -1 depending on doping conditions and prefer to occupy the tetrahedral configuration where it is surrounded by Ga atoms. Our results are in excellent agreement with recent experimental results concerning the dominant charge of IGa, underlining the importance of finite size effects in the calculation of defects.

Original languageEnglish
Article number045211
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number4
Publication statusPublished - 16 Jul 2007
Externally publishedYes


ASJC Scopus subject areas

  • Condensed Matter Physics

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