Anisotropy of the Amplitude of the Giant Quantum Oscillations in the Magnetoacoustic Attenuation in Bismuth

The amplitude of the giant quantum oscillations in the attenuation of longitudinal ultrasonic waves is calculated in a model where the Fermi surface consists of spheroids. The dependence of the amplitude on the direction of an applied magnetic field is compared with the experiment on bismuth by Mase et al. . When the propagation direction is along the bisectrix axis, the agreement is very good. Further, it is shown that the relative amplitudes for the three electron pockets and the hole pocket of bismuth are explained if the deformation potential for each pocket depends on the propagation direction relative to the pocket.