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

Naik, MH and Kundu, S and Maity, I and Jain, M (2020) Origin and evolution of ultraflat bands in twisted bilayer transition metal dichalcogenides: Realization of triangular quantum dots. In: Physical Review B, 102 (7).

	PDF phy_rev_102-07_2020.pdf - Published Version Restricted to Registered users only Download (11MB) | Request a copy
	Video (MP4) cbm_near60.mp4 - Published Supplemental Material Restricted to Registered users only Download (818kB) | Request a copy
	Video (MP4) vbm_near60.mp4 - Published Supplemental Material Restricted to Registered users only Download (961kB) | Request a copy
	Video (MP4) VBM_near0.mp4 - Published Supplemental Material Restricted to Registered users only Download (1MB) | Request a copy

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. © 2020 American Physical Society.

Item Type:	Journal Article
Publication:	Physical Review B
Publisher:	American Physical Society
Additional Information:	The copyright of this article belongs to American Physical Society
Keywords:	Eigenvalues and eigenfunctions; Layered semiconductors; Molybdenum compounds; Nanocrystals; Semiconductor quantum dots; Sulfur compounds, Computational approach; Conduction band edge; Electrons and holes; Equilateral triangles; Quantum dot arrays; Quantum particles; Transition metal dichalcogenides; Valence band edges, Transition metals
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	22 Sep 2020 11:22
Last Modified:	22 Sep 2020 11:22
URI:	http://eprints.iisc.ac.in/id/eprint/66523

Actions (login required)

View Item