Observation of inverse spin Hall effect in bismuth selenide

Bismuth Selenide $({\mathrm{Bi}}_{2}{\mathrm{Se}}_{3})$ is a topological insulator exhibiting helical spin polarization and strong spin-orbit coupling. The spin-orbit coupling links the charge current to spin current via the spin Hall effect (SHE). We demonstrate a ${\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$ spin detector by injecting the pure spin current from a magnetic permalloy layer to a ${\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$ thin film and detect the inverse SHE in ${\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$. The spin Hall angle of ${\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$ is found to be 0.0093 \ifmmode\pm\else\textpm\fi{} 0.0013 and the spin diffusion length in ${\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$ to be 6.2 \ifmmode\pm\else\textpm\fi{} 0.15 nm at room temperature. Our results suggest that topological insulators with strong spin-orbit coupling can be used in functional spintronic devices.