(E,T) phase diagrams in polar compounds

Chiral smectics or banana shaped molecules have attracted much attention due to their ability to present ferroelectric mesophases under field. These properties are often presented as intrinsic to the ground phase at zero-field (i.e. two peaks in the switching current would imply an antiferroelectric ground phase and so on...). We would like to stress here that they have to be related to the full (E, T) phase diagram where the electric field E and the temperature instead are both thermodynamic variables.