Abstract We show that development of polar order may spontaneously destroy the lamellar structure of a liquid crystal. This results in an unusual sequence of phases, with the ferroelectric nematic phase appearing below a non‐polar smectic phase. The effect is related to unfavourable dipole interactions within the smectic layers and can be explained by Landau theory, in which the temperature‐dependent term is non‐monotonic as it is renormalised by spontaneous electric polarisation.
Strachan et al. (Tue,) studied this question.