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Moiré induced topology and flat bands in twisted bilayer WSe2: A first-principles study

Kundu, S and Naik, MH and Krishnamurthy, HR and Jain, M (2022) Moiré induced topology and flat bands in twisted bilayer WSe2: A first-principles study. In: Physical Review B, 105 (8).

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Official URL: https://doi.org/10.1103/PhysRevB.105.L081108


We study the influence of strong spin-orbit interaction on the formation of flat bands in relaxed twisted bilayer WSe2. Flat bands, well separated in energy, emerge at the band edges for twist angles ? near 0° and 60°. For ? near 0°, the interlayer hybridization together with a moiré potential determines the electronic structure. The bands near the valence band edge have nontrivial topology, with Chern numbers equal to +1 or -1. We propose that the nontrivial topology of the first band can be probed experimentally for twist angles less than a critical angle of 3.5°. For ? near 60°, the flattening of the bands arising from the K point of the unit cell Brillouin zone is a result of atomic rearrangements in the individual layers. Our findings on the flat bands and the localization of their wave functions for both ranges of ? match well with recent experimental observations.

Item Type: Journal Article
Publication: Physical Review B
Publisher: American Physical Society
Additional Information: The copyright for this article belongs to the Authors.
Keywords: Electronic structure; Wave functions, Bands edges; Electronic.structure; Energy; First-principle study; Flat band; Hybridisation; Nontrivial topology; Spin-orbit interaction; Twist angles; Twisted bilayers, Topology
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 29 Jun 2022 07:16
Last Modified: 29 Jun 2022 07:16
URI: https://eprints.iisc.ac.in/id/eprint/73858

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