Valley Manipulation by Optically Tuning the Magnetic Proximity Effect in WSe2/CrI3 Heterostructures

Kyle L. Seyler; Ding Zhong; Bevin Huang; Xiayu Linpeng; Nathan P. Wilson; Takashi Taniguchi; Kenji Watanabe; Wang Yao; Di Xiao; Michael A. McGuire; Kai Mei C. Fu; Xiaodong Xu

doi:10.1021/acs.nanolett.8b01105

Valley Manipulation by Optically Tuning the Magnetic Proximity Effect in WSe₂/CrI₃ Heterostructures

Kyle L. Seyler, Ding Zhong, Bevin Huang, Xiayu Linpeng, Nathan P. Wilson, Takashi Taniguchi, Kenji Watanabe, Wang Yao, Di Xiao, Michael A. McGuire, Kai Mei C. Fu, Xiaodong Xu

Correlated Electron Materials

Research output: Contribution to journal › Article › peer-review

317 Scopus citations

Abstract

Monolayer valley semiconductors, such as tungsten diselenide (WSe₂), possess valley pseudospin degrees of freedom that are optically addressable but degenerate in energy. Lifting the energy degeneracy by breaking time-reversal symmetry is vital for valley manipulation. This has been realized by directly applying magnetic fields or via pseudomagnetic fields generated by intense circularly polarized optical pulses. However, sweeping large magnetic fields is impractical for devices, and the pseudomagnetic fields are only effective in the presence of ultrafast laser pulses. The recent rise of two-dimensional (2D) magnets unlocks new approaches to controlling valley physics via van der Waals heterostructure engineering. Here, we demonstrate the wide continuous tuning of the valley polarization and valley Zeeman splitting with small changes in the laser-excitation power in heterostructures formed by monolayer WSe₂ and 2D magnetic chromium triiodide (CrI₃). The valley manipulation is realized via the optical control of the CrI₃ magnetization, which tunes the magnetic exchange field over a range of 20 T. Our results reveal a convenient new path toward the optical control of valley pseudospins and van der Waals magnetic heterostructures.

Original language	English
Pages (from-to)	3823-3828
Number of pages	6
Journal	Nano Letters
Volume	18
Issue number	6
DOIs	https://doi.org/10.1021/acs.nanolett.8b01105
State	Published - Jun 13 2018

Funding

This work is mainly supported by the Department of Energy, Basic Energy Sciences, Materials Sciences and Engineering Division (grant no. DE-SC0018171). Device fabrication is partially supported by University of Washington Innovation Award. W.Y. is supported by the Croucher Foundation (Croucher Innovation Award) and the HKU ORA. Work at ORNL (M.A.M.) was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division. K.W. and T.T. acknowledge support from the Elemental Strategy Initiative conducted by the MEXT, Japan and a Grant-in-Aid for Scientific Research on Innovative Areas “Science of Atomic Layers” from JSPS. D.X. and K.F. acknowledge the support a Cottrell Scholar Award. X.X. acknowledges support from the Clean Energy Institute (funded by the State of Washington) and from the Boeing Distinguished Professorship in Physics.

Keywords

2D magnets
Magnetic proximity effect
transition-metal dichalcogenide
valley
van der Waals heterostructure

Access to Document

10.1021/acs.nanolett.8b01105

Cite this

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title = "Valley Manipulation by Optically Tuning the Magnetic Proximity Effect in WSe2/CrI3 Heterostructures",

abstract = "Monolayer valley semiconductors, such as tungsten diselenide (WSe2), possess valley pseudospin degrees of freedom that are optically addressable but degenerate in energy. Lifting the energy degeneracy by breaking time-reversal symmetry is vital for valley manipulation. This has been realized by directly applying magnetic fields or via pseudomagnetic fields generated by intense circularly polarized optical pulses. However, sweeping large magnetic fields is impractical for devices, and the pseudomagnetic fields are only effective in the presence of ultrafast laser pulses. The recent rise of two-dimensional (2D) magnets unlocks new approaches to controlling valley physics via van der Waals heterostructure engineering. Here, we demonstrate the wide continuous tuning of the valley polarization and valley Zeeman splitting with small changes in the laser-excitation power in heterostructures formed by monolayer WSe2 and 2D magnetic chromium triiodide (CrI3). The valley manipulation is realized via the optical control of the CrI3 magnetization, which tunes the magnetic exchange field over a range of 20 T. Our results reveal a convenient new path toward the optical control of valley pseudospins and van der Waals magnetic heterostructures.",

keywords = "2D magnets, Magnetic proximity effect, transition-metal dichalcogenide, valley, van der Waals heterostructure",

author = "Seyler, {Kyle L.} and Ding Zhong and Bevin Huang and Xiayu Linpeng and Wilson, {Nathan P.} and Takashi Taniguchi and Kenji Watanabe and Wang Yao and Di Xiao and McGuire, {Michael A.} and Fu, {Kai Mei C.} and Xiaodong Xu",

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AU - Zhong, Ding

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AU - Linpeng, Xiayu

AU - Wilson, Nathan P.

AU - Taniguchi, Takashi

AU - Watanabe, Kenji

AU - Yao, Wang

AU - Xiao, Di

AU - McGuire, Michael A.

AU - Fu, Kai Mei C.

AU - Xu, Xiaodong

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