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Controlling Umklapp Scattering in a Bilayer Graphene Moiré Superlattice

Jat, MK and Mishra, S and Mann, HK and Bajaj, R and Watanabe, K and Taniguchi, T and Krishnamurthy, HR and Jain, M and Bid, A (2024) Controlling Umklapp Scattering in a Bilayer Graphene Moiré Superlattice. In: Nano Letters, 24 (7). pp. 2203-2209.

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Official URL: https://doi.org/10.1021/acs.nanolett.3c04223


We present experimental findings on electron-electron scattering in two-dimensional moiré heterostructures with a tunable Fermi wave vector, reciprocal lattice vector, and band gap. We achieve this in high-mobility aligned heterostructures of bilayer graphene (BLG) and hBN. Around the half-full point, the primary contribution to the resistance of these devices arises from Umklapp electron-electron (Uee) scattering, making the resistance of graphene/hBN moiré devices significantly larger than that of non-aligned devices (where Uee is forbidden). We find that the strength of Uee scattering follows a universal scaling with Fermi energy and is nonmonotonically dependent on the superlattice period. The Uee scattering can be tuned with the electric field and is affected by layer polarization of BLG. It has a strong particle-hole asymmetry; the resistance when the chemical potential is in the conduction band is significantly lower than when it is in the valence band, making the electron-doped regime more practical for potential applications. © 2024 American Chemical Society.

Item Type: Journal Article
Publication: Nano Letters
Publisher: American Chemical Society
Additional Information: The copyright for this article belongs to the Authors.
Keywords: Electric fields; Electron scattering; Electrons; Energy gap; Graphene, Bilayer Graphene; Brown�zak oscillation; Electron-electron scattering; Fermi wave vectors; Layer polarization; Moiré superlattice; Reciprocal lattice vectors; Tunables; Two-dimensional; Umklapp scattering, Polarization, graphene, article; bilayer membrane; drug therapy; electric field; electron; oscillation; polarization
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 09 Apr 2024 11:16
Last Modified: 09 Apr 2024 11:16
URI: https://eprints.iisc.ac.in/id/eprint/84679

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