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Title: Direct comparison of current-induced spin polarization in topological insulator Bi2Se3 and InAs Rashba states

Three-dimensional topological insulators (TIs) exhibit time-reversal symmetry protected, linearly dispersing Dirac surface states with spin–momentum locking. Band bending at the TI surface may also lead to coexisting trivial two-dimensional electron gas (2DEG) states with parabolic energy dispersion. A bias current is expected to generate spin polarization in both systems, although with different magnitude and sign. Here we compare spin potentiometric measurements of bias current-generated spin polarization in Bi2Se3(111) where Dirac surface states coexist with trivial 2DEG states, and in InAs(001) where only trivial 2DEG states are present. We observe spin polarization arising from spin–momentum locking in both cases, with opposite signs of the measured spin voltage. We present a model based on spin dependent electrochemical potentials to directly derive the sign expected for the Dirac surface states, and show that the dominant contribution to the current-generated spin polarization in the TI is from the Dirac surface states.
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [1]
  1. Naval Research Lab. (NRL), Washington, DC (United States)
  2. Univ. of Wisconsin, Milwaukee, WI (United States)
  3. Univ. of Wisconsin, Milwaukee, WI (United States); West Virginia Univ., Morgantown, WV (United States)
Publication Date:
Grant/Contract Number:
FG02-05ER46228
Type:
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 7; Journal ID: ISSN 2041-1723
Publisher:
Nature Publishing Group
Research Org:
Univ. of Wisconsin, Milwaukee, WI (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1361624