A. Yu. Kaminskii

Low-temperature ferromagnetism in a new diluted magnetic semiconductor Bi2−xFexTe3

Single crystals of a new diluted magnetic semiconductor Bi2−xFexTe3 (0≤x≤0.08) were grown. For all crystals, the transition into a ferromagnetic state with easy axis parallel to the C3 axis was observed at temperature Tc increasing with iron concentration and reaching 12 K at x=0.08. An increase in the Seebeck coefficient, anomalous Hall effect, and resistivity jump at T=Tc were also observed. The frequency of the de Haas-van Alphen oscillations decreases with increasing x, indicating the donor properties of Fe.

Quantum Hall effect in the bulk semiconductors bismuth and antimony tellurides: Proof of the existence of a current-carrier reservoir

The quantization of the Hall resistivity ρxy in the form of plateaus in the dependence of ρxy on the magnetic field B is observed in the semiconductors Bi2Te3 and Sb2Te3; the minima of the transverse magnetoresistivity ρxx correspond to the start of the plateaus. The quantization of ρxy is due to the presence of a current-carrier reservoir. An impurity band with a high density of states or a different band with a much higher current-carrier effective mass serves as the reservoir.

Influence of silver on the galvanomagnetic properties and energy spectrum of mixed (Bi1− xSbx)2Te3 crystals

An investigation is made of the temperature dependences of the resistivity in the range 4.2–300 K, the Hall effect, and the Shubnikov-de Haas effect in magnetic fields up to 40 T in (Bi1− xSbx)2Te3Agy single crystals (0 ≤ x ≤ 0.75). Doping (Bi1− xSbx)2Te3 crystals with silver showed that in Sb2Te3 and (Bi1− xSbx)2Te3 crystals unlike Bi2Te3 silver exhibits acceptor properties. The angular and concentration dependences of the Shubnikov-de Haas effect were studied in (Bi1− xSbx)2Te3Agy. It was established that the anisotropy of the ellipsoids of the upper valence band in Bi0.5Sb1.5Te3 remains unchanged as a result of silver doping.