Electrical detection of the spin polarization due to charge flow in the   surface state of the topological insulator Bi_1.5 Sb_0.5 Te_1.7 Se_1.3
  We detected the spin polarization due to charge flow in the spin non-degenerate surface state of a three dimensional topological insulator by means of an all-electrical method. The charge current in the bulk-insulating topological insulator Bi1.5Sb0.5Te1.7Se1.3 (BSTS) was injected/extracted through a ferromagnetic electrode made of Ni80Fe20, and an unusual current-direction-dependent magnetoresistance gives evidence for the appearance of spin polarization which leads to a spin-dependent resistance at the BSTS/Ni80Fe20 interface. In contrast, our control experiment on Bi2Se3 gave null result. These observations demonstrate the importance of the Fermi-level control for the electrical detection of the spin polarization in topological insulators. 
Yuichiro Ando (1,2) Takahiro Hamasaki (2), Takayuki Kurokawa (2),   Kouki Ichiba (2), Fan Yang (3), Mario Novak (3), Satoshi...
cond-mat.mtrl-sci cond-mat.mes-hall