抄録
Valence electrons of the boron atom substituting for carbon in 6H silicon carbide have been studied, for the purpose to elucidate the results of electron spin resonance experiment by Woodbury and Ludwig. A theoretical predict has been presented on the basis of tight binding approximation. Partial ionicity of the B-Si bond where the boron atom is positive has been proposed as an origin of small 11B hyperfine interaction compared with 29Si superhyperfine interaction. The opposite signs in the hyperfine constants A and B observed in one spectrum (called I) have been interpreted in terms of a weak trigonal field. Its potential for electron is lower in the direction of the B-Si bond parallel to the c axis. Such a trigonal field is demonstrated in the boron center occupying the site 9d, to which the spectrum I is likely to be assigned. The calculation has also predicted the g|| value to be identical to the free spin’s and the g⊥ value to be slightly larger than it, in good agreement with the values observed in the spectrum I. Similar argument, however, does not apply in the g factors of the other two spectra (called II and III), for which higher order of approximation may be necessary.
