Electronic properties of n‐type (Bi 1− x Sb x ) 2 Te 3 from magneto‐quantum oscillations

The magnetoresistance of n‐type (Bi 1− x Sb x ) 2 Te 3 mixed crystals is investigated in quantizing magnetic fields ( B ≦ 10 T) between 1.6 and 4.2 K. Up to x = 0.3 Shubnikov‐de Haas oscillations can be observed on samples with electron concentrations between 7.8 × 10 17 and 4.4 × 10 18 cm −3 , allowing the evaluation of electronic mass parameters and g ‐factors. The six‐ellipsoid non‐parabolic model for the lowest conduction band of Bi 2 Te 3 can be shown to apply up to about 15% Sb content with unvariable mass parameters but a decreasing tilt angle ζ 0 ( x ) of their principal axes relative to the crystal axes within the mirror planes of the Brillouin zone. Starting from x = 0.2 the Shubnikov‐de Haas patterns are changed drastically due to a cross‐over of two different types of conduction band minima.