Enhancement of surface state contribution in cadmium doped Bi2Se3 single crystal

Cadmium doped topological insulator crystals with the formula CdxBi2-xSe3 were grown using a modified Bridgman technique and their electrical and magnetic transport properties were studied. All samples showed weakly metallic resistivity and the resistivity increased monotonously as the Cd concentration increased. The resistivity data could be fitted by different formulas below and above 30 K in all samples result from different mechanism, which could be explained by the freezing of bulk carriers around 30K. For highly doped samples x = 0.07, simultaneous crossovers in the curves of temperature dependent of resistivity (rho-T) and temperature dependent of magnetoresistance (MR-T) at low temperature were observed. And SdH oscillations were found at 5 and 10 K. These results indicating that the contribution of the surface state was significantly improved. First-principles calculations showed that Cd Bi (substitute one Bi atom by Cd atom) is realistic. (C) 2019 Elsevier B.V. All rights reserved.