Nematic and smectic phases with proper ferroelectric order

A material showing a sequence of three ferroelectric liquid crystalline phases below the paraelectric nematic phase has been synthesized and studied. The polar order of molecules appearing due to the dipole-dipole interactions in the NF phase is preserved also in the smectic phases: orthogonal SmAF and tilted SmCF. The ferroelectric ground state of both smectic phases was confirmed by their second harmonic generation activity and polarization switching. In SmCF phase polarization becomes oriented to electric field by decreasing the tilt angle to zero. Although both smectic phases are ferroelectric in nature, their dielectric response was found to be very different.