Computer study of intrinsic defects in CaWO4

A computer simulation has been performed to study the intrinsic defects in CaWO4. The inter-atomic interaction potentials are empirically fitted to the known crystal properties. The results reveal that the predominant intrinsic defects existed in the crystal should be oxygen Frenkel-type. Calculated formation energies of electronic defects suggest that the hole is easier to be trapped by oxygen ion than by calcium ion, and oxygen would prior to occupy the oxygen vacancy during the annihilation under oxidation atmosphere. An analysis of activation energy shows that oxygen vacancy migration is movable ionic defects in CaWO4.