Enhanced valley splitting in monolayer WSe2 due to magnetic exchange field

Chuan Zhao, Tenzin Norden, Peiyao Zhang, Puqin Zhao, Yingchun Cheng, Fan Sun, James P. Parry, Payam Taheri, Jieqiong Wang, Yihang Yang, Thomas Scrace, Kaifei Kang, Sen Yang, Guo Xing Miao, Renat Sabirianov, George Kioseoglou, Wei Huang, Athos Petrou, Hao Zeng

Research output: Contribution to journalArticlepeer-review

335 Scopus citations


Exploiting the valley degree of freedom to store and manipulate information provides a novel paradigm for future electronics. A monolayer transition-metal dichalcogenide (TMDC) with a broken inversion symmetry possesses two degenerate yet inequivalent valleys1,2, which offers unique opportunities for valley control through the helicity of light3-5. Lifting the valley degeneracy by Zeeman splitting has been demonstrated recently, which may enable valley control by a magnetic field6-9. However, the realized valley splitting is modest (∼0.2 meV TC1). Here we show greatly enhanced valley spitting in monolayer WSe2, utilizing the interfacial magnetic exchange field (MEF) from a ferromagnetic EuS substrate. A valley splitting of 2.5 meV is demonstrated at 1 T by magnetoreflectance measurements and corresponds to an effective exchange field of ∼12 T. Moreover, the splitting follows the magnetization of EuS, a hallmark of the MEF. Utilizing the MEF of a magnetic insulator can induce magnetic order and valley and spin polarization in TMDCs, which may enable valleytronic and quantum-computing applications.

Original languageEnglish (US)
Pages (from-to)757-762
Number of pages6
JournalNature Nanotechnology
Issue number8
StatePublished - Aug 1 2017

ASJC Scopus subject areas

  • Bioengineering
  • Atomic and Molecular Physics, and Optics
  • Biomedical Engineering
  • General Materials Science
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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