Demonstration of surface transport in a hybrid Bi(2)Se(3)/Bi(2)Te(3) heterostructure

In spite of much work on topological insulators (TIs), systematic experiments for TI/TI heterostructures remain absent. We grow a high quality heterostructure containing single quintuple layer (QL) of Bi(2)Se(3) on 19 QLs of Bi(2)Te(3) and compare its transport properties with 20 QLs Bi(2)Se(3) and 20 QLs Bi(2)Te(3). All three films are grown on insulating sapphire (0001) substrates by molecular beam epitaxy (MBE). In situ angle-resolved photoemission spectroscopy (ARPES) provides direct evidence that the surface state of 1 QL Bi(2)Se(3)/19 QLs Bi(2)Te(3) heterostructure is similar to the surface state of the 20 QLs Bi(2)Se(3) and different with that of the 20 QLs Bi(2)Te(3). In ex situ transport measurements, the observed linear magnetoresistance (MR) and weak antilocalization (WAL) of the hybrid heterostructure are similar to that of the pure Bi(2)Se(3) film and not the Bi(2)Te(3) film. This suggests that the single Bi(2)Se(3) layer on top of 19 QLs Bi(2)Te(3) dominates its transport properties.