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

Abstract

AbstractThe resistance and Hall effect are investigated in p‐Bi2Te3 and Bi2Te3〈Sn〉 with tin content x = 0.1 and 0.25 at% and hole concentrations p = (2 to 4) × 1018 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 × 108 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 × 108 Pa all peculiarities of oscillations disappear. It is proposed that tin doping of Bi2Te3 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.