The spin multiplicity of TV2a was unambiguously re-determined by means of pulsed electron nucleus double resonance technique. The TV2a center was one of the most commonly observed defects in 4H-SiC, and its origin was identified as one belonging to a class of negatively charged Si vacancy by means of continuous-wave electron paramagnetic resonance and the two-dimensional nutation method of pulsed electron paramagnetic resonance technique. However, a model with the spin multiplicity of triplet (S=1) and the neutral charge state has recently been suggested. The results clearly showed that TV2a was a quartet spin (S=3/2) state and thus should be single-negatively charged.

Spin Multiplicity and Charge State of a Silicon Vacancy (TV2a) in 4H-SiC Determined by Pulsed ENDOR. N.Mizuochi, S.Yamasaki, H.Takizawa, N.Morishita, T.Ohshima, H.Itoh, T.Umeda, J.Isoya: Physical Review B, 2005, 72[23], 235208 (6pp)