EPR and theoretical studies of positively charged carbon vacancy in 4H-SiC

T. Umeda, J. Isoya, N. Morishita, T. Ohshima, T. Kamiya, A. Gali, P. Deák, N. T. Son, E. Janzén

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Abstract

The carbon vacancy is a dominant defect in 4H-SiC, and the "E15" electron-paramagnetic-resonance (EPR) spectrum originates from positively charged carbon vacancies (VC+) at quasicubic sites. The observed state for EI5, however, has been attributed to a motional-averaged state with the C3v symmetry, and its true atomic structure has not been revealed so far. We here report low temperature (<40 K) EPR measurements on EI5 and show that this center has a C1h-symmetric structure due to Jahn-Teller distortion. We also performed ab inito calculations of the hyperfine tensors for EI5, and obtained a good agreement between experiment and theory in not only their principal values but also their principal axis directions. A good agreement was also demonstrated for the EI6 center (hexagonal-site VC+) in this paper. The transition from EI5(C1h) to EI5(C3v) was found to be thermally activated and its activation energy was measured as 0.014 eV.

Original languageEnglish
Article number235212
Pages (from-to)1-6
Number of pages6
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume70
Issue number23
DOIs
Publication statusPublished - Dec 2004

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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    Umeda, T., Isoya, J., Morishita, N., Ohshima, T., Kamiya, T., Gali, A., Deák, P., Son, N. T., & Janzén, E. (2004). EPR and theoretical studies of positively charged carbon vacancy in 4H-SiC. Physical Review B - Condensed Matter and Materials Physics, 70(23), 1-6. [235212]. https://doi.org/10.1103/PhysRevB.70.235212