Flat Bands and Mechanical Deformation Effects in the Moiré Superlattice of MoS2-WSe2Heterobilayers

Dacen Waters, Yifan Nie, Yifan Nie, Felix Lüpke, Yi Pan, Yi Pan, Stefan Fölsch, Yu Chuan Lin, Bhakti Jariwala, Kehao Zhang, Chong Wang, Hongyan Lv, Hongyan Lv, Kyeongjae Cho, Di Xiao, Joshua A. Robinson, Randall M. Feenstra

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

It has recently been shown that quantum-confined states can appear in epitaxially grown van der Waals material heterobilayers without a rotational misalignment (θ = 0°), associated with flat bands in the Brillouin zone of the moiré pattern formed due to the lattice mismatch of the two layers. Peaks in the local density of states and confinement in a MoS2/WSe2 system was qualitatively described only considering local stacking arrangements, which cause band edge energies to vary spatially. In this work, we report the presence of large in-plane strain variation across the moiré unit cell of a θ = 0° MoS2/WSe2 heterobilayer and show that inclusion of strain variation and out-of-plane displacement in density functional theory calculations greatly improves their agreement with the experimental data. We further explore the role of a twist angle by showing experimental data for a twisted MoS2/WSe2 heterobilayer structure with a twist angle of θ = 15°, which exhibits a moiré pattern but no confinement.

Original languageEnglish (US)
Pages (from-to)7564-7573
Number of pages10
JournalACS nano
Volume14
Issue number6
DOIs
StatePublished - Jun 23 2020

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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