Cooperative interactions in the lattice of LaF$_3$-Type superionic crystals

The mechanism and energy parameters of cooperative interactions between point defects, vacancies, and interstitial ions, in the lattice of LaF$_3$-type superionic trifluorides are studied. The mean energy of interaction between two pairs of the defects is determined ($\lambda$ = 0.032 eV) in the dipole approximation. It is shown that cooperative interactions in the “quasi-liquid” lattice of LaF$_3$ decrease the defect formation energy down to values on the order of $\approx kT$.