Mechanism to Stabilise the Ferrielectric Phase in Ferroelectric Smectics. II ---The Order of the Phase Sequences---

抄録

The nearest neighbour interacting model with the freedom of the sense of molecular long axis was presented previously to certify the assumptions in the ANNNI model with the third nearest neighbour interaction, on the basis of which the successive phase transitions in ferroelectric smectics have been elucidated. The mechanism to give the negative definiteness of the effective second nearest neighbour interaction induced from that model is clarified in the concrete form. By analysing the ground state of the model, various types of the sequences of phase transitions are obtained depending on the four energy parameters, from which the main four phases, ferroelectric, antiferroelectric, ferrielectric and another type of antiferroelectric ones, are proved to appear just in the order observed experimentally.