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 2000818

2D 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

More information

Latest update

2/29/2024