抄録
The temperature induced successive phase transitions of SC variants are observed between SC and SC_A. Ferrielectric and antiferroelectric phases emerge as subphases. And the wave number, q, characterizes these phases, such as SC_γ (3 layer structure, q=1/3) and AF (4 layer structure, q=1/4). In SC_A or AF, it is expected that we can observe the half pitch band, and can't observe the full pitch band as the Bragg reflection, because the layer structure period is 180 deg. But in antiferroelectric subphases that have q=1/(2n) with large n, we may observe the full pitch band. We analyze these possible full pitch bands by using the 4×4 matrix method.
