Temperature dependence and characteristics of relaxation modes in achiral polar smectic phases

Abstract

ABSTRACT The paper studies relaxation modes and their corresponding amplitudes in antiferroelectric polar smectic phases made of achiral bent-core compounds. The analysis identifies two types of modes in the orthogonal phase. The nature of these modes is either pure polar or quasi tilt, but they are split into phase and amplitude modes. One of the amplitude tilt modes is a soft mode and the corresponding relaxations time becomes infinite at the transition to the tilted phase. In tilted phases, characteristic modes change the phase of equilibrium order parameters, the amplitude or both simultaneously. Of these modes, two are predominately polar, soft mode and Goldstone mode are predominately tilt modes and the rest are mixed. The nature of characteristic modes is temperature independent in all studied phases.