Possibility of ferroelectric Jahn-Teller phase transitions was largely neglected in the ferroelectric community so far. Only very recently a nice example has been demonstrated in the crystal of GaV4S8 and in closely related materials. Here we shall address the mechanism and the order-disorder nature of this ferroelectric Jahn-Teller phase transition in terms of a simple phenomenological model. Discussion will be supported by comparison with the results of recently available spectroscopic studies, partly reported in a recent publication[1].
This work was supported by the Czech Science Foundation (Project GACR 17-11494J).
References
[1] J. Hlinka, F. Borodavka, I. Rafalovskyi, Z. Docekalova, J. Pokorny, I. Gregora, V. Tsurkan, H. Nakamura, F. Mayr, C. A. Kuntscher, A. Loidl, S. Bordács, D. Szaller, H.-J. Lee, J. H. Lee, and I. Kézsmárki, Phys. Rev. B 94, 060104(R) (2016).