Spin-Electricity Conversion Induced by Spin Injection into Topological Insulators

We report successful spin injection into the surface states of topological insulators by using a spin pumping technique. By measuring the voltage that shows up across the samples as a result of spin pumping, we demonstrate that a spin-electricity conversion effect takes place in the surface states of bulk-insulating topological insulators Bi1.5Sb0.5Te1.7Se1.3 and Sn-doped Bi2Te2Se. In this process, the injected spins are converted into a charge current along the Hall direction due to the spin-momentum locking on the surface state.