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Anisotropic ultrafast spin/valley dynamics in WTe2 films

Anisotropic ultrafast spin/valley dynamics in WTe2 films

Authors :
Chen, Yequan
Chen, Zhendong
Chen, Yongda
Chen, Liming
Ning, Jiai
Liu, Bo
Zhang, Chunchen
Lu, Xianyang
Ruan, Xuezhong
Liu, Wenqing
Wang, Peng
Song, Fengqi
Zhang, Chunfeng
Wang, Fengqiu
Wu, Jing
He, Liang
Wang, Xuefeng
Zhang, Rong
Xu, Yongbing
Source :
J. Appl. Phys. 131, 163903 (2022)
Publication Year :
2020

Abstract

WTe2 Weyl semimetal hosts the natural broken inversion symmetry and strong spin orbit coupling, making it promising for exotic spin/valley dynamics within a picosecond timescale. Here, we unveil an anisotropic ultrafast spin/valley dynamics in centimeter-scale, single-crystalline Td-WTe2 films using a femtosecond pump-probe technique at room temperature. We observe a transient (~0.8 ps) intra-valley transition and a subsequent polarization duration (~5 ps) during the whole spin/valley relaxation process. Furthermore, the relaxation exhibits the remarkable anisotropy of approximately six-fold and two-fold symmetries due to the intrinsic anisotropy along the crystalline orientation and the extrinsic matrix element effect, respectively. Our results offer a prospect for the ultrafast manipulation of spin/valleytronics in topological quantum materials for dissipationless high-speed spin/valleytronic devices.<br />Comment: 21 pages, 4 figures

Details

Database :
arXiv
Journal :
J. Appl. Phys. 131, 163903 (2022)
Publication Type :
Report
Accession number :
edsarx.2008.08785
Document Type :
Working Paper
Full Text :
https://doi.org/10.1063/5.0090935