Effects of Cl–Cl interaction on phonon dispersion in perovskite type CsPbCl3 Original Research Article

The phonon dispersion curves in three symmetry directions of phase I of CsPbCl3 superionic conductor are calculated by applying the deʹLaunay angular force model. With the third neighbor interaction between Cl–Cl ions, considerable agreements are obtained for all phonon frequencies at zone center (ZC) and also for the acoustic modes in the Δ direction. Two high energy phonon modes at ZC-point are reasonably understood.