The effect of temperatures ranging from 0 K to 1000 K on the positron lifetime of He- or H-vacancy complexes in 3 C -SiC are studied using first-principles calculations. We observed a steady decrease in the formation energy of H-vacancy complexes upon additional H introduction, in contrast to the variation tendency of formation energies seen in He-vacancy complexes. The intrinsic vacancies ( V Si , V C , and V Si + C ) exhibit different decrease in positron lifetime with the addition of He or H atoms, with the effect of He being more pronounced. Moreover, V C and its impurity-vacancy complexes...
