Unconventional Charge–Spin Conversion in Weyl-Semimetal WTe2
Journal article, 2020
An outstanding feature of topological quantum materials is their novel spin topology in the electronic band structures with an expected large charge-to-spin conversion efficiency. Here, a charge-current-induced spin polarization in the type-II Weyl semimetal candidate WTe2 and efficient spin injection and detection in a graphene channel up to room temperature are reported. Contrary to the conventional spin Hall and Rashba–Edelstein effects, the measurements indicate an unconventional charge-to-spin conversion in WTe2, which is primarily forbidden by the crystal symmetry of the system. Such a large spin polarization can be possible in WTe2 due to a reduced crystal symmetry combined with its large spin Berry curvature, spin–orbit interaction with a novel spin-texture of the Fermi states. A robust and practical method is demonstrated for electrical creation and detection of such a spin polarization using both charge-to-spin conversion and its inverse phenomenon and utilized it for efficient spin injection and detection in the graphene channel up to room temperature. These findings open opportunities for utilizing topological Weyl materials as nonmagnetic spin sources in all-electrical van der Waals spintronic circuits and for low-power and high-performance nonvolatile spintronic technologies.
unconventional charge–spin conversion
Edelstein effect
spin-momentum locking
type-II
WTe 2
Weyl-semimetals
graphene
current-induced spin polarization
van der Waals heterostructures
Author
Zhao Bing
University of Science and Technology Beijing
2D-Tech
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
Bogdan Karpiak
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
2D-Tech
Dmitrii Khokhriakov
2D-Tech
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
Annika Johansson
Max Planck Society
Martin-Luther-Universität Halle-Wittenberg
Anamul Md Hoque
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
2D-Tech
Xiaoguang Xu
University of Science and Technology Beijing
Yong Jiang
University of Science and Technology Beijing
I. Mertig
Max Planck Society
Martin-Luther-Universität Halle-Wittenberg
Saroj Prasad Dash
Graphene Centre at Chalmers
2D-Tech
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
Advanced Materials
09359648 (ISSN) 15214095 (eISSN)
Vol. 32 38 20008182D material-based technology for industrial applications (2D-TECH)
VINNOVA (2019-00068), 2020-05-01 -- 2024-12-31.
GKN Aerospace Sweden (2D-tech), 2021-01-01 -- 2024-12-31.
Subject Categories
Atom and Molecular Physics and Optics
Other Physics Topics
Condensed Matter Physics
DOI
10.1002/adma.202000818