Influence of Sn on Galvanomagnetic Properties of Layered p-(Bi1?xSbx)2Te3 Semiconductors

Abstract

The temperature dependence of the resistivity and the Hall effect in the range 0.3–300 K, and the Shubnikov-de Haas effect have been investigated in Sn-doped p-(Bi1—xSbx)2Te3 (0 ≤ x ≤ 1.0) single crystals. Doping of (Bi1—xSbx)2Te3 with tin showed that Sn exhibits acceptor properties in all crystals. The anomalous temperature and magnetic field behavior of the Hall coefficient was explained quantitatively by a model, which involves the complicated two-valence band structure of p-(Bi1—xSbx)2Te3. The quantization of the Hall resistivity ϱH in the form of plateaus in the dependence of ϱH on the magnetic field B is observed. The minima of the transverse magnetoresistivity ϱ correspond to the start of plateaus. The oscillation of ϱH is due to the presence of a carrier reservoir. An impurity resonant band with a high density of states in Sb2Te3 or the second lower valence band with a higher hole effective mass in (Bi1—xSbx)2Te3 serves as the reservoir. The valence band structure of (Bi1—xSbx)2Te3 is also discussed.