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We present experimental findings on electron-electron scattering in two-dimensional moiré heterostructures with 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 half-filling, the primary contribution to the resistance of these devices arises from electron-electron Umklapp (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 has a non-monotonic dependence on superlattice period. The Uee scattering is electric field tunable 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 lesser than when it is in the valence band, making the electron-doped regime more practical for potential applications.

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• In Copyright
  

  This document is the Accepted Manuscript version of a Published Work that appeared in final form in Nano Letters, copyright © 2024 American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.nanolett.3c04223.

Keyword: Umklapp scattering, Brown-Zak oscillations, Bilayer graphene, Moiré superlattice, Layer polarization

Date published: 2024-02-21

Publisher: American Chemical Society (ACS)

Journal:

• Nano Letters (ISSN: 15306984) vol. 24 issue. 7 p. 2203-2209

Funding:

• Ministry of Education, India
• DEVCOM Army Research Laboratory FA5209 22P0166
• Ministry of Education, Culture, Sports, Science and Technology
• Science and Engineering Research Board
• Department of Science and Technology, Ministry of Science and Technology, India DST/SJF/PSA-01/2016-17
• Department of Science and Technology, Ministry of Science and Technology, India SB/DF/005/2017
• Department of Science and Technology, Ministry of Science and Technology, India DST/NSM/R&D_HPC Applications/2021/23
• Japan Society for the Promotion of Science 23H02052
• Japan Society for the Promotion of Science 21H05233

Manuscript type: Author's version (Accepted manuscript)

MDR DOI:

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

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Updated at: 2025-07-24 08:30:18 +0900

Published on MDR: 2025-07-24 08:18:23 +0900