The molecular origin of ferroelectricity in FLC: A challenge for dielectric spectroscopy at microwave frequencies

Broadband dielectric spectroscopy delivers in the frequency regime from 10 Hz to 10 GHz two collective relaxation processes (soft— and Goldstone—mode) and one molecular relaxation (β-relaxation). The latter does not split or broaden at the phase transition SmA*/SmC*. Its dielectric strength does not decline - in pronounced contrast to the (generalized) Landau theory of the phase transition SmA*/SmC* in FLC. Our experimental findings contradict the common explanation of the spontaneous polarization which is based on the existence of a free rotation inside the SmA* phase and its strong hindrance in the ferroelectric SmC* phase.