Opposite current-induced spin polarizations in bulk-metallic Bi2Se3 and bulk-insulating Bi2Te2Se topological insulator thin flakes
- Purdue Univ., West Lafayette, IN (United States); Univ. of Wyoming, Laramie, WY (United States)
- Univ. of Iowa, Iowa City, IA (United States)
- Purdue Univ., West Lafayette, IN (United States)
- Purdue Univ., West Lafayette, IN (United States); Aarhus Univ. (Denmark)
One of the most fundamental and exotic properties of 3D topological insulators (TIs) is spin-momentumlocking (SML) of their topological surface states (TSSs), promising for potential applications in future spintronics. However, other possible conduction channels, such as a trivial two-dimensional electron gas (2DEG) with strong Rashba type spin-orbit interaction (SOI) and bulk conducting states that may possess a spin Hall effect (SHE), can coexist in 3D TIs, making determining the origin of the current induced spin polarization (CISP) difficult. In this work, we directly compared the CISP between bulk-insulating Bi2Te2Se (BTS221) and bulk-metallic Bi2Se3 thin flakes using spin potentiometry. In the bulk insulating BTS221, the observed CISP has a sign consistent with the expected helicity of the SML of the TSS, but an opposite sign to its calculated bulk spin Hall conductivity (SHC). However, compared to BTS221, an opposite CISP is observed in the bulk metallic Bi2Se3, consistent instead with both the expectations of its Rashba-Edelstein effect of the band-bending induced 2DEG and bulk spin Hall Effect (SHE). Our results provide an electrical way to distinguish the TSS from other possible conducting channels in spin transport measurements on 3D TIs, and open ways for the potential applications in charge-spin conversion devices.
- Research Organization:
- Univ. of Wyoming, Laramie, WY (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division; Defense Advanced Research Projects Agency (DARPA); National Science Foundation (NSF); USDOE
- Grant/Contract Number:
- SC0020074; SC0021281; N66001-11-1-4107; EFMA-1641101; DMR-1420451
- OSTI ID:
- 1780999
- Alternate ID(s):
- OSTI ID: 2335853
- Journal Information:
- Physical Review B, Vol. 103, Issue 3; ISSN 2469-9950
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
Point-contact Andreev reflection spectroscopy on Bi 2 Se 3 single crystals
Deficiency of the bulk spin Hall effect model for spin-orbit torques in magnetic-insulator/heavy-metal heterostructures