Reply to "comment on 'High-pressure phases of group-II difluorides: Polymorphism and superionicity' "

Abstract

Cazorla et al. (preceding Comment) criticize our recent results on the high-PT phase diagram of CaF2 [Phys. Rev. B 95, 054118 (2017)]. According to our analysis, Cazorla et al. have not converged their calculations with respect to simulation cell size, undermining the Comment's conclusions about both the high-T behavior of the P62m-CaF2 polymorph, and the use of the QHA in our work. As such, we take this opportunity to emphasize the importance of correctly converging molecular-dynamics simulations to avoid finite-size errors. We compare our quasiharmonic phase diagram for CaF2 with currently available experimental data, and we find it to be entirely consistent and in qualitative agreement with such data. Our prediction of a superionic phase transition in P62m-CaF2 (made on the basis of the QHA) is shown to be accurate, and we argue that simple descriptors, such as phonon frequencies, can offer valuable insight and predictive power concerning superionic behavior.