Quantifying van der waals interactions in layered transition metal dichalcogenides from pressure-enhanced valence band splitting

Penghong Ci, Yabin Chen, Jun Kang, Ryuji Suzuki, Hwan Sung Choe, Joonki Suh, Changhyun Ko, Taegyun Park, Ke Shen, Yoshihiro Iwasa, Sefaattin Tongay, Joel W. Ager, Lin Wang Wang, Junqiao Wu

Research output: Contribution to journalArticle

16 Scopus citations

Abstract

van der Waals (vdW) forces, despite being relatively weak, hold the layers together in transition metal dichalcogenides (TMDs) and play a key role in their band structure evolution, hence profoundly affecting their physical properties. In this work, we experimentally probe the vdW interactions in MoS2 and other TMDs by measuring the valence band maximum (VBM) splitting (δ) at K point as a function of pressure in a diamond anvil cell. As high pressure increases interlayer wave function coupling, the VBM splitting is enhanced in 2H-stacked MoS2 multilayers but, due to its specific geometry, not in 3R-stacked multilayers, hence allowing the interlayer contribution to be separated out of the total VBM splitting, as well as predicting a negative pressure (2.4 GPa) where the interlayer contribution vanishes. This negative pressure represents the threshold vdW interaction beyond which neighboring layers are electronically decoupled. This approach is compared to first-principles calculations and found to be widely applicable to other group-VI TMDs.

Original languageEnglish (US)
Pages (from-to)4982-4988
Number of pages7
JournalNano Letters
Volume17
Issue number8
DOIs
StatePublished - Aug 9 2017

Keywords

  • 3R-stacked MoS
  • diamond anvil cell
  • interlayer wave function coupling
  • spin-orbital coupling
  • van der Waals interaction

ASJC Scopus subject areas

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

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  • Cite this

    Ci, P., Chen, Y., Kang, J., Suzuki, R., Choe, H. S., Suh, J., Ko, C., Park, T., Shen, K., Iwasa, Y., Tongay, S., Ager, J. W., Wang, L. W., & Wu, J. (2017). Quantifying van der waals interactions in layered transition metal dichalcogenides from pressure-enhanced valence band splitting. Nano Letters, 17(8), 4982-4988. https://doi.org/10.1021/acs.nanolett.7b02159