Theoretical Study of Hysteresis Phenomena of Pressure-Induced Polymorphic Transition in Alkali Halides

Abstract

The lattice energy was calculated on the way of the transition of KCl by the use of the transition mechanism proposed by Watanabe et al., and it was found that the potential barrier appeared between two phases, the B1 and the B2 structures. Due to the existence of the potential barrier, it was indicated that the hysteresis phenomena were derived in the pressure-induced polymorphic transition, and that the width of the hysteresis could be obtained quantitatively. The temperature dependence of the hysteresis also can be explained by the concept that the barrier can be got over by the thermal energy.