Giant Quantum Oscillations of Ultrasonic Absorption in Bismuth

Abstract

Changes in the magnetoacoustic attenuation of bismuth at 1,4-4.2K and in magnetic field 2-10 kG are measured. The longitudinal sound wave of 40-200 MHz is propagated along the trigonal axis while the magnetic field vector is parallel to the binary-trigonal plane. For the changes in the attenuation which could be as much as 50 dB. two distinct G.Q.O., each periodic in the reciprocal of the magnetic field, were observed; the dominant oscillations evidently quench the weaker ones when the two periods are the same. The spin splitting and the line shape of the G.Q.O. are used to estimate the effective g-factor and mass of carriers. The inclination of the ellipsoid axis to the basal plane is inferred from the period to be about 4°. The basic tool was a superheterodyne system coupled into a synchronous detector which enabled the traversed sample length to be increased upto 20 cm. Some relevant current theories and experimental data for comparison are used in the text.