POINT-DEFECTS AND ION MIGRATION IN PBFCL

Atomistic simulation techniques have been applied to PbFCI in order to calculate the energetics ofdefect formation and ion transport mechanisms in the undoped material. Schottky-like disorder is computed to be the dominant ionic defect. The activation energies for a variety of anion vacancy migration mechanisms are calculated and found to be in good agreement with experiment. The results support the models in which the low temperature ionic conductivity is attributed to an interplanar Cl vacancy mechanism. We predict that the out-of-plane configuration of the Cl2- species is the most stable self-trapped hole (Vk center). Interatomic separations of the Vk centers following lattice relaxation are also discussed. © 1990 Academic Press, Inc.