Large positive magnetoresistance with high Hall mobility and intercalation of Fe dopants in the quenched Bi2Te3 single crystals.

A study of Fe-ion intercalation in Bi 2 Te 3 probed by the x-ray diffraction, magnetization, Hall measurement, and spectra of synchrotron x-ray photoemission spectroscopy is reported, in which a large positive magnetoresistance (MR) and a high carrier mobility for applications have been achieved and probed in the quenched Fe x Bi 2 Te 3 single crystals with x = 0.01 and 0.15. Large positive MR of ∼470% with a Hall mobility of ∼44000 cm2/Vs at 5 K and 6 T has been observed on a quenched Fe 0.01 Bi 2 Te 3 sample with a quenching temperature T q of 400 °C, where the electrical parameters can be tuned by T q. Larger c -axis lattice constants and electron-dominant carriers in the quenched samples lead to the inference that the doped Fe atoms are mostly located at the intercalated van der Waals gap positions and exist as a metallic state of Fe0, which is confirmed by the synchrotron x-ray photoemission spectroscopy (XPS) spectra. Combining the x-ray diffraction, magnetization, and Hall-coefficient studies, here we pave a simple way for probing into the location of Fe dopants in Bi 2 Te 3. In addition, novel magnetotransports of Fe-doped Bi 2 Te 3 associated with the absence of ferromagnetism have been presented, and satisfy the scenario that the topological surface state persists without the loss of topological insulating characteristics of the linear band dispersion, and the large MR may originate from the surface magnetism, even in the presence of Fe impurities. This study also discusses the huge enhancement of Hall mobility arising from the surface Dirac electrons that are accompanied with a modified band structure in quenched Fe 0.01 Bi 2 Te 3. • This paper reports on the c-axis crystalline structure, magnetization, and magnetotransport properties of quenched Fe-doped Bi 2 Te 3 single crystals, which have been at the center of debate over magnetically doped topological insulators. • Stable magnetoresistance of ∼470% with a Hall mobility of ∼44000 cm2/Vs at 5 K and 6 T has been observed on the quenched sample, leading to the conclusion that this material is suitable for applications in next-generation photoelectrical devices and spintronics. • In the quenched samples, it can be inferred that the doped Fe atoms are mostly located at the intercalated van der Waals gap positions and exist within metallic state of Fe0. • Here a simple way is presented, for the first time, to probe into the location of impurity atoms in Bi 2 Te 3. [ABSTRACT FROM AUTHOR]