| AVS 63rd International Symposium & Exhibition | |
| Scanning Probe Microscopy Focus Topic | Monday Sessions |
| Session SP+2D+AS+NS+SS-MoA |
| Session: | Probing Topological States And Superconductivity |
| Presenter: | Saban Hus, Oak Ridge National Laboratory |
| Authors: | S. Hus, Oak Ridge National Laboratory Y. Chen, Purdue University A.-P. Li, Oak Ridge National Laboratory |
| Correspondent: | Click to Email |
Charge currents carried by the nontrivial surface states of topological insulators (TIs) exhibit a net spin polarization due to spin-momentum locking. Electrical detection of such a spin polarization is crucial for technological applications. However, in 3D TI materials the existence of a bulk conduction channel makes it difficult to quantify the density and the spin polarization of the current carried by the surface states. Here we report in-situ, spin sensitive four-probe spectroscopy measurements on Bi2Te2Se single crystals. A ferromagnetic probe detects the net spin accumulation on the surface states while a set of four-probe spectroscopy measurement is used for a quantitative separation of 2D and 3D conduction. We also examine the effect of surface doping by residual gas molecules on the current induced spin polarization. Even though, the additional carriers by dopants enhance the 2D conductance in TIs they reduce the net spin polarization of current carried by topological surface states.
This research was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility.