Dept. of Solid State Electron., Huazhong Univ. of Sci. and Technol., Wuhan 430074, People's Republic of China
In a ferroelectric 180(degrees) multilayered domain structure, the ferroelectric domain layer wave (FDLW) propagating along the domain interface would cause a periodic electric potential field [X. J. Li et al., J. Phys. C 2, 9577--9588 (1991)]. The periodic potential field would split the energy band of electrons into subbands called the ``minigap.'' The feature of the minigap is that it depends on the existence of FDLW because the wave vector and amplitude of FDLW would affect the minigap structure. This is different from the normal superlattice in which the minigap is determined. In addition, the periodic potential fields have the symmetry vibration modes and asymmetry vibration modes corresponding to the same dispersion relation of FDLW, while the displacements of the two opposite domains are asymmetry and symmetry, respectively. The calculating results of the subband in ferroelectric 180(degrees) domain superlattice have shown that the subband variation with the vector k of FDLW is similar to the subband variation with periodic width of superlattice.