A phenomenological theory that describes the phase transitions from a liquid of achiral molecules to the periodic antiferroelectric mesophases is presented. The transitions are shown to be driven by the vector-wave condensation mechanism. Resulting ordered phases have the structure of a vector wave with linear, circular, or elliptic polarization. The phase diagram, the stability with respect to spatial modulation, and the behavior in an external field are discussed in relation with the recently discovered achiral antiferroelectric liquid crystals.

• Received 1 October 1998

DOI:https://doi.org/10.1103/PhysRevLett.82.940