MAGNETOACOUSTIC ATTENUATION IN SEMIMETALS .1. EXTRAORDINARILY LARGE ATTENUATION PEAK IN BISMUTH FOR Q OR H APPROXIMATELY 90-DEGREES

The sound attenuation in bismuth at low temperature has been measured under the conditions: the longitudinal sound wave vector q is applied along the trigonal axis and the field if is parallel to a trigonal-bisectrix plane. For qΛH= 88.0° ±0.3° and 92.2° ±0.3°, a quite large attenuation peak has been found, which is due to the second and third lowest Landau levels of the electrons in the degenerated non-principal electron pockets. Its attenuation coefficient α(T, Hp) shows fairly strong temperature dependence and frequency dependence as compared with those in other orientations. A theoretical analysis is presented to explain a part of the anomalies. © 1979, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.