Ab initio study of substitutional nitrogen in GaAs

W. Orellana, A. C. Ferraz

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


We investigate the atomic geometry, formation energies, and electronic structure of nitrogen occupying both arsenic and gallium sites in GaAs (NAs and NGa) using first-principles total-energy calculations. We find that both neutral defects induce impurity-like empty levels in the band gap acting as acceptors. While NAs shows a s-like a1 level in the middle of the band gap, NGa shows a p-like t2 level close to the bottom of the conduction band. The gap level of NAs gives theoretical support for the experimentally observed band-edge redshift on the GaAsN alloy for a N concentration ∼3%. Strong inward relaxations preserving the Td symmetry characterize the NAs equilibrium geometry in all the charge states investigated. In contrast, NGa exhibits a structural metastability in neutral charge state and Jahn-Teller off-center distortions in negative charge states forming a negative-U center. Formation energies of competing NAs and NGa defects are also discussed.

Original languageEnglish
Pages (from-to)1231-1233
Number of pages3
JournalApplied Physics Letters
Issue number9
Publication statusPublished - 26 Feb 2001

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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