Shubnikov-de Haas Effect in Dilute Bismuth-Antimony Alloys. I. Quantum Oscillations in Low Magnetic Fields

The Shubnikov-de Haas oscillations in the transverse magnetoresistance of Bi-Sb systems were observed at temperatures 1.65, 2.2, and 4.2°K for the concentration of Sb ranging 0-1 at.% with a magnetic field (0-10 kG) in the trigonal plane. No apparent spin splitting was observed in this range of magnetic field at these temperatures. The two-band model was found in good agreement with all our results. The change of the extremal cross section $S$ of the Fermi surface was found to be independent of the orientation. To a good approximation, both $S$ and the Fermi energy were found to vary linearly with the Sb concentration in these dilute alloys. Comparisons between other experimental results and our data indicate that certain band parameters should be nonlinear functions of the Sb concentration before the band overlap vanishes.