Giant Valley-Zeeman Splitting from Spin-Singlet and Spin-Triplet Interlayer Excitons in WSe2/MoSe2 Heterostructure

Tianmeng Wang, Shengnan Miao, Zhipeng Li, Yuze Meng, Zhengguang Lu, Zhen Lian, Mark Blei, Takashi Taniguchi, Kenji Watanabe, Sefaattin Tongay, Dmitry Smirnov, Su Fei Shi

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

Transition metal dichalcogenides (TMDCs) heterostructure with a type II alignment hosts unique interlayer excitons with the possibility of spin-triplet and spin-singlet states. However, the associated spectroscopy signatures remain elusive, strongly hindering the understanding of the Moiré potential modulation of the interlayer exciton. In this work, we unambiguously identify the spin-singlet and spin-triplet interlayer excitons in the WSe2/MoSe2 heterobilayer with a 60° twist angle through the gate- and magnetic field-dependent photoluminescence spectroscopy. Both the singlet and triplet interlayer excitons show giant valley-Zeeman splitting between the K and K′ valleys, a result of the large Landé g-factor of the singlet interlayer exciton and triplet interlayer exciton, which are experimentally determined to be ∼10.7 and ∼15.2, respectively, which is in good agreement with theoretical expectation. The photoluminescence (PL) from the singlet and triplet interlayer excitons show opposite helicities, determined by the atomic registry. Helicity-resolved photoluminescence excitation (PLE) spectroscopy study shows that both singlet and triplet interlayer excitons are highly valley-polarized at the resonant excitation with the valley polarization of the singlet interlayer exciton approaching unity at ∼20 K. The highly valley-polarized singlet and triplet interlayer excitons with giant valley-Zeeman splitting inspire future applications in spintronics and valleytronics.

Original languageEnglish (US)
Pages (from-to)694-700
Number of pages7
JournalNano Letters
Volume20
Issue number1
DOIs
StatePublished - Jan 8 2020

Keywords

  • Interlayer exciton
  • Zeeman shift
  • singlet
  • triplet
  • valley polarization

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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    Wang, T., Miao, S., Li, Z., Meng, Y., Lu, Z., Lian, Z., Blei, M., Taniguchi, T., Watanabe, K., Tongay, S., Smirnov, D., & Shi, S. F. (2020). Giant Valley-Zeeman Splitting from Spin-Singlet and Spin-Triplet Interlayer Excitons in WSe2/MoSe2 Heterostructure. Nano Letters, 20(1), 694-700. https://doi.org/10.1021/acs.nanolett.9b04528