Calculation of positron lifetimes and momentum distributions of electron-positron annihilation radiation in Mg-doped 3C-SiC

We calculated the formation energies of various charge states for MgC, MgSi, MgSi + VC, and MgC + VSi defects in 3C-SiC to assess their thermodynamic stability. Using the two-component density functional theory, we determined the positron annihilation lifetimes at 0 K, temperature-dependent positron annihilation lifetimes while considering the electron-phonon coupling interactions, and the positron densities in various charge states of these defects in 3C-SiC. Additionally, the electron-positron momentum distributions were analyzed. Our calculated results largely agree with previous calculations and experimental data, providing a database for the identification of impurity-vacancy complexes in 3C-SiC.