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Title: Site of Mn in Mn {delta}-doped GaAs: X-ray absorption spectroscopy

Journal Article · · Physical Review. B, Condensed Matter and Materials Physics
DOI:https://doi.org/10.1103/PHYSREVB.73.0· OSTI ID:20787844
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  1. CNR-INFM-OGG, c/o ESRF, GILDA CRG, 6 Rue Jules Horowitz, F-38043 Grenoble (France)

In order to determine the local structure of Mn in {delta}-doped GaAs layers we have carried out an x-ray absorption spectroscopy experiment at the Mn-K edge in samples grown by molecular beam epitaxy with and without Be co-doping. Mn-Mn atomic correlations have not been found within {approx}5 A radius, ruling out the presence of metallic clusters or local Mn enrichment. In samples deposited at 300 deg. C, Mn substitutionally occupies the Ga site with a local expansion ({approx_equal}2%) of the first-neighbor distance with respect to GaAs; the second neighbors remain at a distance very close to that of the host lattice, indicating that the structural perturbation induced by Mn is very localized. Ab initio simulation of the x-ray absorption near edge structure spectra confirmed that Mn enters the Ga, rather than the As, site. Samples grown at 450 deg. C exhibit a reduction of the first shell coordination number, suggesting the initial phases of MnAs precipitation. In the case of Be co-doping the downward shift of the Fermi energy leads to the appearance of Mn in tetrahedral interstitial sites, of which we provide a previously unavailable local structural description.

OSTI ID:
20787844
Journal Information:
Physical Review. B, Condensed Matter and Materials Physics, Vol. 73, Issue 3; Other Information: DOI: 10.1103/PhysRevB.73.035314; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
Country of Publication:
United States
Language:
English