Acousto-electric interactions in semicondctors using the two-band model

The effects of collisions and non-parabolicity of the energy bands on magneto-acoustic phenomena were investigated with special reference to those narrow band gap semiconductors in which the dominant electron-phonon interaction is via the piezoelectric coupling mechanism. The electromagnetic response of the electron system to the piezoelectrically induced electromagnetic field which accompanies the ultrasonic wave in a piezoelectric semiconductor was calculated. Expressions were derived to the effective conductivity tensor for the g-vector parallel to b-vector configuration in the cases of a constant relaxation time and that of an energy dependent relaxation time. For the g-vector transverse to b-vector configuration, only the case of constant relaxation time was considered. The dispersion relation was found from which the absorption coefficient alpha and the relative change in the sound velocity can be determined.