Shubnikov-de Haas effect in dilute bismuth-antimony alloys. II. Quantum oscillations in high magnetic fields

The transverse magnetoresistance of a dilute Bi-Sb system was measured at 4.2°K with a magnetic field (up to 80 kG and above) in the trigonal plane. The Shubnikov-de Haas oscillations due to holes were observed systematically. The electron Fermi energy for the alloys was found to decrease with the magnetic field in a similar fashion to that for pure Bi. The hole Fermi energies were found to increase with the magnetic field. Through numerical analyses, we suggest that the energy overlap of the conduction band and the valence band should decrease with the magnetic field for both pure Bi and the alloys. Spin splitting effect for holes was observed for the Bi-Sb alloy of 0.95-at.% Sb concentration. For this alloy, the spin effective mass Ms was found to be approximately 2.6 times larger than the orbital effective mass Mc[Ms(2.60.4)Mc] in the trigonal plane.