Dept. of Solid State Electron., Huazhong Univ. of Sci. and Technol., Wuhan 430074, People's Republic of China
Penn State Univ., University Park, PA 16802
Ferroelectric domain layer wave (FDLW) [X. Li, J. Appl. Phys. 56, 88 (1984)] would be induced by the ultrasonic wave in the ferroelectric 180(degrees) domain superlattice. There exist many new phenomena under the action of FDLW. Its characteristics sum up an elementary excitation ``domainon'' [X. Li et al., J. Phys.: Condensed Matter 2, 9577 (1990)]. It has been shown that the domainons subband can be formed by the interaction between domainons and electrons at the conductive band or holes at the valence band of ferroelectric 180(degrees) domain superlattice, in other words, under the action of the ultrasonic wave, the domainons would change the distribution of electrons or holes and affect the electric properties of ferroelectrics. In addition, the variation of the subband generated by ultrasonic wave with the vector k of FDLW is similar to the variation of the subband with periodic width of superlattice. The characteristics of the symmetry domainons and asymmetry domainons have been discussed. Further analysis above that 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.