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Isotopic heterogeneity in synthetic and natural silicon carbide |
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| Authors: | A.A. Shiryaev M. Wiedenbeck V.B. Polyakov A.A. Lebedev |
| Affiliation: | a Shubnikov Institute of Crystallography RAS, Leninsky pr. 59, 119333 Moscow, Russia b GeoForschungsZentrum, Telegrafenberg, 14473 Potsdam, Germany c Institute of Geology and Mineralogy, SB RAS, pr. Ak.Koptyuga 3, 630090 Novossibirsk, Russia d Institute of Experimental Mineralogy RAS, Chernogolovka, Russia e Lebedev Physics Institute RAS, Leninsky pr. 53, Moscow, Russia f Ioffe Physico-Technical Institute RAS, 194021 Sankt Petersburg, Russia g Linkoping University, 58183 Linkoping, Sweden |
| Abstract: | The distribution of both carbon and silicon isotopes in synthetic sublimation growth SiC wafers and in natural SiC grains was studied using secondary ion mass-spectrometry (SIMS). Significant variations in both isotopic ratios were observed which were broadly correlated with the crystalline perfection as documented by Raman microspectroscopy. Domains consisting of 15R (or with its admixture) are, on average, enriched in 12C isotope relative to 6H domains, and they also show larger scatter in their observed silicon isotope ratios. We ascribe such heterogeneity to fluctuations of Si/C ratio in the growth medium and it is possible to model the spatial extent of such fluctuations. For the natural SiC grains the isotopic data suggest that they grew under relatively stable conditions, although some of them show significant isotopic zoning. |
| Keywords: | A. Inorganic compounds B. Crystal growth C. Raman spectroscopy |
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