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

摘要

Atomically smooth, single crystalline (Bi_1-xSb_x)₂Te₃ 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 (Bi_0.5Sb_0.5)₂Te₃ sample. These highly tunable (Bi_1-xSb_x)₂Te₃ thin films provide an excellent platform to explore the intrinsic transport properties of the three-dimensional topological insulators.