Gallium self-interstitial relaxation in Gallium Arsenide: an {ab initio} characterization

Abstract

Ga interstitials in GaAs ($I_{Ga}$) 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${}_{[\mathrm{Ga}-\mathrm{As}]}$, 111-split${}_{[\mathrm{Ga}-\mathrm{As}]}$, and 100-split${}_{[\mathrm{Ga}-\mathrm{Ga}]}$. Studying the competition between various configuration and charges of $I_{Ga}$, 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 $I_{Ga}$, underlining the importance of finite size effects in the calculation of defects.

arXiv commentv1) 18 pages, 5 figures, submitted to PRB (Latex preprint version) v2) 9 pages, 5 figures, reviewed version resubmitted to PRB (correction to equation 1, some changes and reformulations, minor grammatical and typo corrections, added reference)

References in corpus (6)

• The SIESTA method for ab initio order-N materials simulation
• Efficient index handling of multidimensional periodic boundary conditions
• Managing the supercell approximation for charged defects in semiconductors: finite size scaling, charge correction factors, the bandgap problem and the ab initio dielectric constant
• Self-vacancies in Gallium Arsenide: an ab initio calculation
• First-principles study of As interstitials in GaAs: Convergence, relaxation, and formation energy
• Charge-dependent migration pathways for the Ga vacancy in GaAs

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• Optical orientation and spin-dependent recombination in GaAsN alloys under continuous-wave pumping
• Modeling the Ga/As binary system across temperaturesand compositions from first principles
• Gallium interstitial contributions to diffusion in gallium arsenide