Origin and evolution of ultraflat bands in twisted bilayer transition metal dichalcogenides: Realization of triangular quantum dots

Mit H. Naik, Sudipta Kundu, Indrajit Maity, and Manish Jain
Phys. Rev. B 102, 075413 – Published 7 August 2020
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Abstract

Using a multiscale computational approach, we probe the origin and evolution of ultraflat bands in moiré superlattices of twisted bilayer MoS2, a prototypical transition metal dichalcogenide. Unlike twisted bilayer graphene, we find no unique magic angles in twisted bilayer MoS2 for flat-band formation. Ultraflat bands form at the valence band edge for twist angles (θ) close to 0 and at both the valence and conduction band edges for θ close to 60, and have distinct origins. For θ close to 0, inhomogeneous hybridization in the reconstructed moiré superlattice is sufficient to explain the formation of flat bands. For θ close to 60, additionally, local strains cause the formation of modulating triangular potential wells such that electrons and holes are spatially separated. This leads to multiple energy-separated ultraflat bands at the band edges closely resembling eigenfunctions of a quantum particle in an equilateral triangle well. Twisted bilayer transition metal dichalcogenides are thus suitable candidates for the realization of ordered quantum dot array.

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  • Received 27 August 2019
  • Revised 16 June 2020
  • Accepted 20 July 2020

DOI:https://doi.org/10.1103/PhysRevB.102.075413

©2020 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Mit H. Naik*, Sudipta Kundu, Indrajit Maity, and Manish Jain

  • Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India

  • *Present address: Department of Physics, University of California at Berkeley, California 94720, USA; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
  • mjain@iisc.ac.in

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Issue

Vol. 102, Iss. 7 — 15 August 2020

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