Spin-Polarized Tunneling Study on Spin-Momentum Locking in the   Topological Insulators
  We demonstrate that the charge-spin conversion efficiency of topological insulators (TI) can be experimentally determined by injecting spin-polarized tunneling electrons into a TI. Through a comparative study between bismuth selenide and bismuth antimony telluride, we verified the topological-surface-state origin of the observed giant spin signals. By injecting energetic electrons into bismuth selenide, we further studied the energy dependence of the effective spin polarization at the TI surface. The experimentally verified large spin polarization, as well as our calculations, provides new insights into optimizing TI materials for near room-temperature spintronic applications. 
Luqiao Liu, A. Richardella, Ion Garate, Yu Zhu, N. Samarth and   Ching-Tzu Chen
cond-mat.mes-hall