Manipulating the magneto-resistance of Bi2Se3 thin films by strontium doping

We systematically studied the magneto-resistance of strontium (Sr) doped topological insulator (TI) Bi2Se3 films. For Bi2Se3 films with relatively large classic magneto-resistance, we found that slightly Sr doping can completely suppress the classic magneto-resistance and make the weak antilocalization effect dominate in the weak-magnetic-field region. Consequently, the value of the magneto-resistance is enhanced by more than 2.7 times at 0.2 T in slightly doped samples. In contrast, in the strong-magnetic-field region, the magneto-resistance is strongly reduced by doping but exhibits linear magneto-resistance behavior. Our results suggest that the linear magneto-resistance behavior originates from the mobility fluctuation induced by disorder described by the Parish–Littlewood model. Our findings not only gain insights into the doping effect on the topological insulator but also provide an effective way to manipulate the magneto-transport properties of TI for potential applications in future.