Magnetic field-dependent resistance crossover and anomalous magnetoresistance in topological insulator Bi2Te3

Abstract

We report a metal-insulator like transition in single-crystalline 3D topological insulator Bi2Te3 at a temperature of 230 K in the presence of an external magnetic field applied normal to the surface. This transition becomes more prominent at larger magnetic field strength with the residual resistance value increasing linearly with the magnetic field. At low temperature, the magnetic field dependence of the magnetoresistance shows a transition from logarithmic to linear behavior and the onset magnetic field value for this transition decreases with increasing temperature. The logarithmic magnetoresistance indicates the weak anti-localization of the surface Dirac electrons while the high temperature behavior originates from the bulk carriers due to intrinsic impurities. At even higher temperatures beyond ~230 K, a completely classical Lorentz model type quadratic behavior of the magnetoresistance is observed. We also show that the experimentally observed anomalies at ~230 K in the magneto-transport properties do not originate from any stacking fault in Bi2Te3.