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Nano Research

Article Title

Enhanced linear magneto-resistance near the Dirac point in topological insulator Bi2(Te1−xSex)3 nanowires

Keywords

Topological insulator, nanowire, ambipolar conduction, bismuth selenide, bismuth telluride, linear magneto-resistance, weak anti-localization

Abstract

We report the composition and back-gate voltage tuned transport properties of ternary compound Bi2(Te1−xSex)3 nanowires synthesized by chemical vapor deposition (CVD). It is found that the population of bulk carriers can be suppressed effectively with increasing the Se concentration x. In Bi2(Te1−xSex)3 nanowires with x = 25% ± 5%, the ambipolar surface conduction associated with tuning the Fermi energy across the Dirac point of topological surface states is induced by applying a back-gate voltage. Importantly, we find that while the magnetoresistance (MR) follows the weak antilocalization (WAL) behavior when the Fermi level is tuned away from the Dirac point, MR is enhanced in magnitude and turns more linear in the whole magnetic field range (between ±9 T) near the Dirac point. The observation of the enhanced linear magneto-resistance (LMR) and crossover from WAL to LMR, near the Dirac point provides a deeper insight into understanding the nature of topological insulator’s surface transport and the relation between these two widely observed magneto-transport phenomena.

Graphical Abstract

Publisher

Tsinghua University Press

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