THEORETICAL-STUDY OF THE CHEVRON LAYER STRUCTURE IN SMECTIC PHASES

In this work, a simple soliton model is proposed to explain the chevron layer structure in smectic phases. It is shown that a compression energy related to the molecular tilt results in the chevron structure in the SmC or SmC* phases, and that a coupling energy between the layer compression and the density change via the SmAN phase transition plays an essential role for that in the SmA phase. The temperature dependence of the layer tilt angle and the transition layer thickness is discussed to examine the validity of the present theoretical results. In addition, the external field effect on the layer tilt angle is investigated within a low field approximation. © 1990.