Upper limit of mobility and concentration of charge carriers in fluoride superionic conductors with fluorite and tysonite structures

Within the framework of a crystal-physical model, the maximum values of mobility and concentration of charge carriers in fluoride superionic conductors belonging to the structural types of fluorite (CaF2, SrF2, BaF2, PbF2) and tysonite (LaF3) were calculated. It has been shown that the upper limit of ionic conductivity, mobility and charge carrier concentration in the crystalline state of fluoride superionics is 4 ± 1 S/cm, (5 ± 1) × 10–3 cm2/(сВ) и (5 ± 2) × 1021 cm–3 (10 ± 4% of the total fluoride ions), respectively.