Papers by Keyword: Zero-Field Splitting

Abstract: Nowadays, computational techniques can greatly facilitate the identification of point defect related photoluminescence and EPR centers in semiconductors. Once the identification has been achieved, one can gain a detailed description of the microstructure and the electron configuration of the defect, providing a basis for further understanding and development. Recently, the importance of divacancy and related point defects in different polytypes of SiC has substantially increased due to their possible quantum bit application. However, their different configurations have not been satisfactorily identified yet. In our study, we carry out large-scale first principles supercell calculations to identify the divacancy related point defects in 4H and 6H-SiC. By resolving some general accuracy issues of usual ab initio supercell techniques, we are able to obtain convergent photoluminescence (PL) energies, zero-field-splitting, and hyperfine parameters. Our results confirm the previous assignment of the PL1-4 PL lines in 4H-SiC (also known as UD-2 luminescence lines previously) to the four possible divacancy configurations and provide the identification of QL1,QL2, and QL6 PL lines in 6H-SiC. In all cases the calculated zero-field and hyperfine tensors’ parameters are provided.

Abstract: We calculated the hyperfine structure and the zero-field splitting parameters of divacancies in 3C, 4H and 6H SiC in the ground state and in the excited state for 4H SiC within the framework of density functional theory. Besides that our calculations provide identification of the defect in different polytypes, we can find some carbon atoms next to the divacancy that of the spin polarizations are similar in the ground and excited states. This coherent nuclear spin polarization phenomenon can be the base to utilize ¹³C spins as quantum memory.