THE ELECTROSTATIC POLARIZATION OF FERROELECTRIC LIQUID-CRYSTALS - A NEW INTERPRETATION OF THE TRIANGLE-WAVE TECHNIQUE

We show that the electrostatic polarization measured in ferroelectric liquid crystals using the standard triangle-wave technique is not the total polarization of the sample, but rather a specific nonlinear comp onent of the total polarization. We present a Landau theory to calcula te this nonlinear component explicitly. In the high-temperature limit, above the smectic-A-smectic-C phase transition, the theory predicts that the observed polarization scales as E3/(T - T(AC))4, where T is t he temperature and E the applied electric field. In the low-temperatur e limit, the observed polarization approaches the total polarization. These theoretical predictions are consistent with experimental measure ments.