Highly tunable electron transport in epitaxial topological insulator (Bi1-xSbx)2Te3 thin films

Atomically smooth, single crystalline (Bi1-xSbx)(2)Te-3 films have been grown on SrTiO3(111) substrates by molecular beam epitaxy. A full range of Sb-Bi compositions have been studied in order to obtain the lowest possible bulk conductivity. For the samples with optimized Sb compositions (x = 0.5 +/- 0.1), the carrier type can be tuned from n-type to p-type across the whole thickness with the help of a back-gate. Linear magnetoresistance has been observed at gate voltages close to the maximum in the longitudinal resistance of a (Bi0.5Sb0.5)(2)Te-3 sample. These highly tunable (Bi1-xSbx)(2)Te-3 thin films provide an excellent platform to explore the intrinsic transport properties of the three-dimensional topological insulators. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4754108]