Complex temperature dependence of the dielectric response in simple SmC* phases

Abstract

The system under study has a SmA*↔SmC* phase sequence and is described by a basic phenomenological model. However, in contrast to a common approach, changes of the polarisation induced by the external electric field are considered independent of changes of the tilt. As a result, even in the basic model, which does not contain any additional terms usually used to obtain better fits to experimental observations, the frequencies of most of the relaxation modes depend on the temperature non-linearly and their dielectric response is not inversely proportional to the frequency of the mode. The behaviour is a direct consequence of chiral piezoelectric coupling, which influences the polar properties of the relaxation modes depending on the temperature.