Superballistic flow of viscous electron fluid through graphene constrictions

Krishna Kumar, Roshan and Bandurin, D. A. and Pellegrino, F. M. D. and Cao, Y. and Principi, A. and Guo, H. and Auton, G. H. and Ben Shalom, Moshe and Ponomarenko, Leonid Alexandrovich and Falkovich, G. and Watanabe, K. and Taniguchi, T. and Grigorieva, I. V. and Levitov, L. S. and Polini, M. and Geim, A. K. (2017) Superballistic flow of viscous electron fluid through graphene constrictions. Nature physics. ISSN 1745-2473

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Abstract

Electron–electron (e–e) collisions can impact transport in a variety of surprising and sometimes counterintuitive ways1,2,3,4,5,6. Despite strong interest, experiments on the subject proved challenging because of the simultaneous presence of different scattering mechanisms that suppress or obscure consequences of e–e scattering7,8,9,10,11. Only recently, sufficiently clean electron systems with transport dominated by e–e collisions have become available, showing behaviour characteristic of highly viscous fluids12,13,14. Here we study electron transport through graphene constrictions and show that their conductance below 150 K increases with increasing temperature, in stark contrast to the metallic character of doped graphene15. Notably, the measured conductance exceeds the maximum conductance possible for free electrons16,17. This anomalous behaviour is attributed to collective movement of interacting electrons, which ‘shields’ individual carriers from momentum loss at sample boundaries18,19. The measurements allow us to identify the conductance contribution arising due to electron viscosity and determine its temperature dependence. Besides fundamental interest, our work shows that viscous effects can facilitate high-mobility transport at elevated temperatures, a potentially useful behaviour for designing graphene-based devices.

Item Type:
Journal Article
Journal or Publication Title:
Nature physics
Additional Information:
© 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved.
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/3100
Subjects:
ID Code:
88305
Deposited By:
Deposited On:
19 Oct 2017 15:40
Refereed?:
Yes
Published?:
Published
Last Modified:
27 Sep 2020 04:08