Magnetoresistance and Hall Effect in Bi₂Te₃〈Sn〉 in Ultrahigh Magnetic Fields and under Pressure

Abstract

Abstract The resistance and Hall effect are investigated in p‐Bi 2 Te 3 and Bi 2 Te 3 〈Sn〉 with tin content x = 0.1 and 0.25 at% and hole concentrations p = (2 to 4) × 10 18 cm −‐3 in the temperature range 0.5 K ≦ T ≦ 300 K, at stationary magnetic fields 0 ≦ B ≦ 22 T and under hydrostatic pressure 0 ≦ P ≦ 5.3 × 10 8 Pa. In the samples containing Sn the oscillations of resistance (Shubnikov‐de Haas effect (SdH)) show an anomalously high amplitude and the oscillations of Hall voltage show plateaus. In the ultrahigh region of magnetic fields the magnetoresistance and Hall resistance are practically constant. Under hydrostatic pressures P > 3 × 10 8 Pa all peculiarities of oscillations disappear. It is proposed that tin doping of Bi 2 Te 3 leads to the appearance of an impurity band with high density of states not far from the maximum of the heavy hole band which stabilizes the Fermi level. Under hydrostatic pressure the light hole band rises relatively to the heavy hole band and carriers flow from the impurity band into the light hole band, which leads to the disappearance of peculiarities of oscillations in tin doped samples.