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Description:

In electronic systems with strong electron-electron interactions, charge carriers can exhibit fluidlike behavior governed by viscosity. While such hydrodynamic regimes have been observed in pristine graphene, realizing similar behavior in moiré superlattices has been challenging due to enhanced momentum-relaxing umklapp electron-electron scattering. Here, we show that placing a graphene/hBN superlattice in close proximity to a conductive screening layer suppresses umklapp momentum relaxation, creating favorable conditions for the observation of viscous electron flow. The hydrodynamic response near the first Dirac point remains largely insensitive to the moiré potential, allowing clear observation of the viscous Hall effect and extraction of the electron-electron scattering length. These results identify proximity screening as a practical route to tune scattering processes and enable quantitative measurement of electron viscosity in moiré superlattices. In contrast, transport near the secondary Dirac points is strongly affected by narrow bandwidth, which hinders reliable measurements of the viscous Hall effect in this regime. This limitation highlights the need for multicomponent hydrodynamic frameworks to describe narrow-bandwidth moiré systems.

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• In Copyright
  

  @ American Physical Society

Keyword: Hydrodynamic electron transport, Moiré superlattice, Graphene

Date published: 2025-11-04

Publisher: American Physical Society (APS)

Journal:

• Physical Review B (ISSN: 1550235X) vol. 112 issue. 20 L201404

Funding:

• National Research Foundation of Korea
• Ministry of Science and ICT, South Korea RS-2024–00444725
• Ministry of Science and ICT, South Korea RS-2022-NR071693
• Ministry of Science and ICT, South Korea RS-2023–00303081
• Ministry of Science and ICT, South Korea RS-2024–00410027
• Natural Science Foundation of Zhejiang Province XHD23A2001
• Japan Society for the Promotion of Science 21H05233
• Japan Society for the Promotion of Science 23H02052
• Japan Society for the Promotion of Science JPMJCR24A5
• Japan Science and Technology Corporation
• Ministry of Education, Culture, Sports, Science and Technology

Manuscript type: Author's version (Accepted manuscript)

MDR DOI:

First published URL: https://doi.org/10.1103/mvtf-mbvq

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Updated at: 2026-06-26 17:26:31 +0900

Published on MDR: 2026-06-26 18:28:48 +0900