Magnetoresistance in doped Bi0.85Sb0.15 single crystals

We have studied the influence of donor and acceptor doping on the magnetotransport properties in Bi0.85Sb0.15 single crystals, which show the properties of a topological band insulator. High-quality Bi0.85Sb0.15 single crystals with tellurium (Te) and tin (Sn) doping from 5 × 10−5 at. % to 10−3 at. % were grown using the Czochralski technique. High carrier mobilities up to 5.8 × 105 cm2 V−1 s−1 at 77 K were achieved in these single crystals. Doping Bi0.85Sb0.15 single crystal with Te at a level of 10−4 at. % gave the highest magnetoresistance at temperatures of 120–200 K. A very high magnetoresistance of 1640% was reached in Sn-doped (10−4 at. %) single crystals in a magnetic field of 1.15 T at 90 K. The influences of Te and Sn doping of Bi1–xSbx single crystals and of magnetic field on the thermal activation energy gap were studied. The observed high magnetoresistance in doped Bi0.85Sb0.15 single crystals could be useful for practical applications in magnetic sensors and multifunctional electromagnetic devices.