Current-generated spin in topological insulators (TIs) has been shown to efficiently switch FM magnetization via spin-orbit torque (SOT) with much lower critical currently densities. However, TI bulk are often degenerately doped and can shunt current from the surface states. Here we demonstrate SOT switching from bulk-insulating Bi2Se3, obtained by growth on BiInSe/In2Se3 buffer layers by MBE, with significantly reduced critical current density than conventional “bulk-conducting” Bi2Se3. We further grew epitaxial In2Se3 tunnel barriers on Bi2Se3, and demonstrate its spin sensitivity, towards further minimize current shunting through the FM metal and overall power consumption for magnetization switching.
|