Flatbands and Mechanical Deformation Effects in the Moiré Superlattice of MoS${}_2$-WSe${}_2$ Heterobilayers

Abstract

It has recently been shown that quantum-confined states can appear in epitaxially grown van der Waals material heterobilayers without a rotational misalignment ($\theta =0^{\circ }$), 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 MoS${}_2$/WSe${}_2$ 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 $\theta =0^{\circ }$ MoS${}_2$/WSe${}_2$ 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 twist-angle by showing experimental data for a twisted MoS${}_2$/WSe${}_2$ heterobilayer structure with twist angle of $\theta =15^{\circ }$, that exhibits a moiré pattern but no confinement.

13 pages, 6 figures in main text. Supporting information included with 13 pages, 8 figures, and 2 tables

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Cited by in corpus (12)

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• Room temperature wavelike exciton transport in a van der Waals superatomic semiconductor
• Visualizing the microscopic origins of topology in twisted molybdenum ditelluride
• Direct STM Measurements of R- and H-type Twisted MoSe2/WSe2 Heterostructures
• Quantum spin Hall edge states and interlayer coupling in twisted-bilayer WTe${}_2$
• Evolution of flat bands in MoSe${}_2$/WSe${}_2$ moiré lattices: A study combining machine learning and band unfolding methods
• One-Dimensional Moiré Physics and Chemistry in Heterostrained Bilayer Graphene
• Influence of atomic relaxations on the moiré flat band wavefunctions in antiparallel twisted bilayer WS${}_{\text{2}}$
• Piezoelectric Electrostatic Superlattices in Monolayer MoS${}_2$
• Twister: Construction and structural relaxation of commensurate moiré superlattices