On the Double-Kink Layer Structure in Smectic Phases

To account for the experimental fact that the X-ray diffraction indicates the triple peaks near the transition point in the smectic phases, we propose here a double-kink soliton model as a φ 6 -system, extending the previous φ 4 -model. The present model indicates a variety of layer structure depending on a phenomenological parameter. The layer structure derived by this model seems to be qualitatively consistent with the experimentally found one.