The EI5 and EI6 centers are typical intrinsic defects in radiation-damaged and semi-insulating 4H-SiC. So far, their origins have been assigned to positively charged carbon vacancies (VC+) and silicon antisites (SiC+), respectively. However, our complete set of 29Si hyperfine (HF) data clearly reveals that both the centers should originate from VC+ but their locations are different, i.e., quasicubic sites for EI5 and hexagonal sites for EI6, as recently predicted by the first-principle calculation [M. Bockstedte et al., Phys. Rev. B 67, 193102 (2003)]. The two types of VC+ centers showed remarkable differences in their atomic structures as well as in the temperature dependence of HF interactions, which are closely related to the nature of the two sites.
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机译：EI5和EI6中心是辐射损坏且半绝缘的4H-SiC中的典型固有缺陷。到目前为止，它们的起源已分别指定为带正电的碳空位（VC +）和硅反位点（SiC +）。然而，我们完整的29Si超细（HF）数据集清楚地表明，这两个中心都应源自VC +，但它们的位置不同，即EI5的准位和EI6的六角位，如第一原则计算最近预测的[ M. Bockstedte等，Phys。 B 67，193102（2003）。两种类型的VC +中心在原子结构以及HF相互作用的温度依赖性方面均显示出显着差异，这与两个位点的性质密切相关。
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