Universität zu Köln

Yang, Fan ORCID: 0000-0001-6841-1605, Ghatak, Subhamoy, Taskin, A. A., Segawa, Kouji, Ando, Yuichiro, Shiraishi, Masashi ORCID: 0000-0003-0592-2824, Kanai, Yasushi ORCID: 0000-0002-6501-9699, Matsumoto, Kazuhiko, Rosch, Achim ORCID: 0000-0002-6586-5721 and Ando, Yoichi ORCID: 0000-0002-3553-3355 (2016). Switching of charge-current-induced spin polarization in the topological insulator BiSbTeSe2. Phys. Rev. B, 94 (7). COLLEGE PK: AMER PHYSICAL SOC. ISSN 2469-9969

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Abstract

The charge-current-induced spin polarization is a key property of topological insulators for their applications in spintronics. However, topological surface states are expected to give rise to only one type of spin polarization for a given current direction, which has been a limiting factor for spin manipulations. Here, we report that in devices based on the bulk-insulating topological insulator BiSbTeSe2, an unexpected switching of spin polarization was observed upon changing the chemical potential. The spin polarization expected from the topological surface states was detected in a heavily electron-doped device, whereas the opposite polarization was reproducibly observed in devices with low carrier densities. We propose that the latter type of spin polarization stems from topologically trivial two-dimensional states with a large Rashba spin splitting, which are caused by a strong band bending at the surface of BiSbTeSe2 beneath the ferromagnetic electrode used as a spin detector. This finding paves the way for realizing the spin transistor operation in future topological spintronic devices.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Yang, Fan UNSPECIFIED orcid.org/0000-0001-6841-1605 UNSPECIFIED Ghatak, Subhamoy UNSPECIFIED UNSPECIFIED UNSPECIFIED Taskin, A. A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Segawa, Kouji UNSPECIFIED UNSPECIFIED UNSPECIFIED Ando, Yuichiro UNSPECIFIED UNSPECIFIED UNSPECIFIED Shiraishi, Masashi UNSPECIFIED orcid.org/0000-0003-0592-2824 UNSPECIFIED Kanai, Yasushi UNSPECIFIED orcid.org/0000-0002-6501-9699 UNSPECIFIED Matsumoto, Kazuhiko UNSPECIFIED UNSPECIFIED UNSPECIFIED Rosch, Achim UNSPECIFIED orcid.org/0000-0002-6586-5721 UNSPECIFIED Ando, Yoichi UNSPECIFIED orcid.org/0000-0002-3553-3355 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-266775
DOI:	10.1103/PhysRevB.94.075304
Journal or Publication Title:	Phys. Rev. B
Volume:	94
Number:	7
Date:	2016
Publisher:	AMER PHYSICAL SOC
Place of Publication:	COLLEGE PK
ISSN:	2469-9969
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Physics > Institute of Physics II
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language ELECTRICAL DETECTION; SURFACE; INJECTION; MAGNETIZATION; GRAPHENE; TORQUE; STATE; METAL Multiple languages Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/26677