Ab initio ELNES/XANES spectral calculation of polar and non-polar grain boundaries in β-SiC Original Research Article

A recently developed ab initio method for the ELNES/XANES spectral calculation for solids is applied to two SiC{1 2 2} Σ=9 grain boundary models in β-SiC. Two such models with polar and non-polar interfaces each containing Si–Si and C–C wrong bonds were used. The method takes into account the electron core–hole interaction and includes all dipole transition matrix elements rigorously. The results show considerable differences in the C–K, Si–K and Si–L edges of atoms in the grain boundary region and those in the bulk-like region. The changes are greater for the Si edges than the C edges. In the presence of wrong bonds, the atoms involved can have very significant differences in their ELNES/XANES spectra. These changes are interpreted with separate calculations of atom-resolved partial density of states, the effective charges on each atom, and the bond order values for each pairs of atoms for all atoms in the grain boundary models.