Native, and rare-earth-created, point defects in the β-phase were studied within the framework of the pair-potential approximation, coupled with a shell-model description of the lattice ions. For the perfect lattice, a set of potential parameters was derived that reproduced the structure, and elastic and dielectric, constants. The calculated formation energies for native defects suggested that anion Frenkel disorder was preferred over cation Frenkel and Schottky-like disorder. The predicted temperature behavior of the conductivity agreed well with available experimental data. In rare-earth doped material, the site-preference of the charge-compensating F interstitial appeared to change from nearest-neighbor to next-nearest neighbor with increasing rare-earth ionic radius.
Theoretical Study of Native and Rare-Earth Defect Complexes in β-PbF2. H.Jiang, A.Costales, M.A.Blanco, M.Gu, R.Pandey, J.D.Gale: Physical Review B, 2000, 62, 803–9