Investigation of the highest valence band in (Bi1‐xSbx)2Te3 crystals

Making use of the Shubnikov‐de Haas effect an investigation is made of the electronic parameters of p‐type (Bi1−xSbx)2Te3 crystals (0 < x < 1) prepared by a vertical Bridgman technique. Magnetic fields up to 10 T flux density are available, the crystal temperature at experiment is between 1.6 to 4.2 K. In the whole range, up to 90% antmony content, p‐type crystals can be prepared, allowing the observation of magnetoresistance oscillations in quantizing magnetic fields at least for B ∥︁ c (c trigonal axis). Up to x = 0.6 the results may be explained in the Bi2Te3 ellipsoidal non‐parabolic model for the constant energy surfaces, where the tilt angle of the principal axes increases monotonously with Sb content while the principal mass parameters remain constant. Simultaneously the g‐tensor components vary monotonously with the composition. For x > 0.6 the obtained data on highly doped samples are no longer complete in order to draw reliable conclusions, thouth it is obvious that the Fermi surfaces change their shape. The energy gap between both different valence band maxima, which are occupied at high hole concentrations, is approx imately constant in the whole range of the mixed crystal system.