First-principles estimations were made of the formation energies of F self-interstitials (Fx’-) and F vacancies (VF+) in CaF2–BaF2 superlattices and in the bulk compounds. In the case of dislocation-free strained-layer superlattices, the calculations predicted that both the Fx’- and the VF+ defects would be energetically more stable in the CaF2 layers than in the BaF2 layers. When the misfit stress in the superlattices was released by dislocations, it was predicted that charge transfer between the layers would become energetically favorable; with Fx’- in the CaF2 layers and VF+ in the BaF2 layers. These conclusions were consistent with experiment.

Localization of Intrinsic Defects in CaF2–BaF2 Superlattices. R.Kagimura, H.Chacham, T.M.Schmidt, R.H.Miwa: Applied Physics Letters, 2003, 83[20], 4154-6