Analysis of the spin splitting of maxima of quantum oscillations of the resistivity of n-Bi-Sb semiconductor alloys in a magnetic field parallel to the bisector axis

Abstract

In samples of semiconductor alloys n-Bi0.93Sb0.07 with different electron concentrations (n1 = 8 × 1015 cm−3, n2 = 1.2 × 1017 cm−3, and n3 = 1.9 × 1018 cm−3), dependences of the electrical resistivity on magnetic fields up to 45 T parallel to the current and the bisector axis (H ‖ C1 ‖ j) have been measured at temperatures of 1.5, 4.5, and 10 K. The obtained dependences ρ22(H) demonstrate quantum oscillations of the resistivity (Shubnikov-de Haas effect), and, in high magnetic fields, there is a resistivity maximum far away from other maxima. On assumption that this maximum is related to the spin-split Landau level N = 0− for electrons of the main ellipsoid, the spin-splitting parameters are calculated for electrons of the main ellipsoid: γ1 = 0.87, γ2 = 0.8, and γ3 = 0.73. Using these values, the oscillation maxima can be reliably related to the numbers of split Landau levels for electrons of the main and secondary ellipsoids. The dependences of the resistivity ρ11 and the Hall coefficient R31.2 on magnetic field have been measured in a transverse magnetic field at H ‖ C1 and j ‖ C2 on the sample with the electron concentration n4 = 1.4 × 1017 cm−3. Using similar analysis, the spin-splitting parameter is found to be γ4 = 0.85, which is close to the value of γ2 = 0.8 obtained for the sample with close electron concentration (n2 = 1.2 × 1017 cm−3) during the measurements in a longitudinal magnetic field. The quantum oscillation maxima of Hall coefficient R31.2 are shifted to the range of high magnetic fields as compared to the quantum oscillation maxima of resistivity ρ11.