Enhanced electron-phonon coupling in doubly aligned hexagonal boron nitride bilayer graphene heterostructure

Kuiri, M and Srivastav, SK and Ray, S and Watanabe, K and Taniguchi, T and Das, T and Das, A (2021) Enhanced electron-phonon coupling in doubly aligned hexagonal boron nitride bilayer graphene heterostructure. In: Physical Review B, 103 (11).

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Abstract

The relative twist angle in heterostructures of two-dimensional materials with similar lattice constants results in a dramatic alteration of the electronic properties. Here, we investigate the electrical and magnetotransport properties in bilayer graphene encapsulated between two hexagonal boron nitride (hBN) crystals, where the top and bottom hBN are rotationally aligned with the bilayer graphene with a twist angle θt�0° andθb<1°, respectively. This results in the formation of two moiré superlattices, with the appearance of satellite resistivity peaks at carrier densities ns1 and ns2, in both hole- and electron-doped regions, together with the resistivity peak at zero carrier density. Furthermore, we measure the temperature (T) dependence of the resistivity (�). The resistivity shows a linear increment with temperature within the range 10 to 50 K for the density regime ns1<n<ns2 with a large slope d�/dT�8.5�/K. The large slope of d�/dT is attributed to the enhanced electron-phonon coupling arising due to the suppression of Fermi velocity in the reconstructed minibands, which was theoretically predicted recently in doubly aligned graphene with top and bottom hBN. Our result establishes the ability of the doubly aligned moiré system to tune the strength of electron-phonon coupling and to modify the electronic properties of multilayered heterostructures. © 2021 American Physical Society.

Item Type:	Journal Article
Publication:	Physical Review B
Publisher:	American Physical Society
Additional Information:	The copyright for this article belongs to American Physical Society
Keywords:	Boron nitride; Electron correlations; Electron-phonon interactions; Electronic properties; Electrons; III-V semiconductors; Lattice constants; Nitrides, Bilayer Graphene; Electron phonon couplings; Fermi velocities; Hexagonal boron nitride; Hexagonal boron nitride (h-BN); Linear increment; Magneto transport properties; Two-dimensional materials, Graphene
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	19 Apr 2021 11:37
Last Modified:	19 Apr 2021 11:37
URI:	http://eprints.iisc.ac.in/id/eprint/68635

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