抄録
The theory of Liu and Toxen for the ultrasonic attenuation is extended to the case where crossed magnetic and electric fields exist. A study is made of the effect of the finite life time of conduction electrons on the ultrasonic amplification in semimetals, in particular on the de Haas type oscillations (i) and the giant quantum oscillations (ii). In the region (i) the effect of the finite life time appears strongly as ultrasonic waves propagate nearly perpendicular to the magnetic field. In the region (ii) the shape and the width of the amplification peaks are not very sensitive to the details of impurity scattering and the width is not modified heavily by the electric field. The theory of Gurevich et al. for the giant quantum oscillations of the ultrasonic attenuation is turned out to be valid if their level width is doubled.
