| Summary: | Magnetotransport properties with a large positive magnetoresistance (MR) and a high carrier mobility for applications have been achieved and probed for quenched Fe _0.01 Bi _2 Te _3 single crystals. Large positive MR of ∼470% with a Hall mobility of ∼44 000 cm ^2 V ^−1 s ^−1 at 5 K and 6 T has been observed on a quenched Fe _0.01 Bi _2 Te _3 sample, in which the electrical parameters can be tuned by the quenching temperature T _q . The MR behaviors for the quenched samples show a crossover from a weak antilocalization-dominant MR to a linear and non-saturating MR at temperatures of T * ≈ 58−100 K, where the large MR at low temperatures possibly originates from the mechanism of topologically protected backscattering. On the contrary, the MR behaviors for the strain-released sample do not show such a distinct crossover, where only linear-like and non-saturating MR behaviors can be observed. Different electrical transports between the quenched and strain-released samples indicate that the band structure, as well as the surface Dirac electrons in Fe _0.01 Bi _2 Te _3 , can be modified by the lattice strain. Furthermore, it is found that the low-temperature magnetoconductivity can be well described by the weak-antilocalization transport formula, while the high-field linear-like MR at T > T * can be explained in terms of Abrikosov’s quantum transport of Dirac-cone states in quenched Fe _0.01 Bi _2 Te _3 single crystals.
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