We have carried out systematical ab initio calculations to study the stability of vacancy clusters and their effect on helium behaviors in 3C-SiC. It is found that the formation energies of vacancy clusters containing only carbon vacancies are the lowest although the vacancies are not closest to each other, while the binding energies of vacancy clusters composed of both silicon and carbon vacancies in the closest neighbors to each other are the highest. Vacancy clusters can provide with free space for helium atoms to aggregate, while interstitial sites are not favorable for helium atoms to accumulate. The binding energies of vacancy clusters with helium atoms increase almost linearly with the ratio of helium to vacancy, n/m. The binding strength of vacancy cluster having the participation of the silicon vacancy with helium is relatively stronger than that without silicon vacancy. The vacancy clusters with more vacancies can trap helium atoms more tightly. With the presence of vacancy clusters in the material, the diffusivity of helium will be significantly reduced. Moreover, the three-dimension electron density is calculated to analyze the interplay of vacancy clusters with helium.

我们已经进行了系统的从头算计算，以研究空位簇的稳定性及其对3C-SiC中氦行为的影响。研究发现，尽管空位彼此之间不是最接近的，但仅包含碳空位的空位簇的形成能是最低的，而由硅和碳空位组成的空位簇的结合能是彼此最接近的。最高。空位簇可以为氦原子聚集提供自由空间，而间隙位置不利于氦原子积累。空位团簇与氦原子的结合能几乎随氦空位比n / m线性增加。具有硅空位和氦的参与的空位团簇的结合强度比没有硅空位的簇的结合强度相对强。具有更多空位的空位簇可以更紧密地捕获氦原子。由于材料中存在空位团簇，氦气的扩散率将大大降低。此外，计算了三维电子密度，以分析空位簇与氦的相互作用。