Giant Quantum Attenuation of Sound Waves in Bismuth. I. Spin Splitting Factors of Electrons and Holes

The giant quantum attenuation of longitudinal sound waves in bismuth was investigated in pulsed magnetic fields up to 170 kG, at a temperature of 1.65°K and at sound wave frequencies of 60 and 100 Mc/s. The angle between the sound wave vector q and the magnetic field vector H was varied by rotating a sample. By combining data in a previous paper with the present ones the anisotropy of the spin splitting factor for electrons in the principal pocket is completely determined for two cases H ∥ X Y -plane and H ∥ Y Z -plane, where X -, Y - and Z -axis refer to a binary, a bisectrix and the trigonal axis, respectively. The Baraff theory is successfully applied to interpret the anisotropy, and values of some parameters in the theory are determined. The hole spin splitting factor for the case H ∥ Z -axis is found conclusively to be (1.86±0.02).