Magnetoresistive effect of a topological-insulator waveguide in the presence of a magnetic field

We investigate the transport properties of a topological insulator (TI) waveguide in the presence of an external magnetic field. We demonstrate that the magnetic field can modulate the energy gap induced by the transverse confinement and may even result in the closure of the band gap. The dependence of the magnetic field and the temperature on the magnetoresistance (MR) is also analyzed. The MR ratio increases linearly and exhibits a nonsaturation behaviour at high fields. The MR behavior also exhibits weak temperature dependence such that a high MR is maintained over a broad temperature range. The robustness of the MR up to room temperature can be exploited for magneto-electronic device applications. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4773489]