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11:42
Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
Published on: July 24, 2015
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Negative local resistance caused by viscous electron backflow in graphene
D A Bandurin1, I Torre2, R Krishna Kumar3
1School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
Science (New York, N.Y.)
|February 26, 2016
Summary
Scientists observed electrons behaving as a viscous liquid in graphene, forming whirlpools and exhibiting hydrodynamic phenomena. This discovery opens new avenues for studying electron hydrodynamics in advanced materials.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Electronics
Background:
- Graphene possesses a unique electron system with weak electron-phonon scattering and frequent electron-electron collisions.
- Above liquid nitrogen temperature, graphene electrons can achieve local equilibrium, behaving like a viscous liquid and exhibiting hydrodynamic phenomena.
Purpose of the Study:
- To provide strong evidence for the electron hydrodynamic transport regime in doped graphene.
- To investigate the viscous properties of the electron liquid in graphene.
Main Methods:
- Experimental observation of anomalous voltage drops in doped graphene near current-injection contacts.
- Analysis of electron flow patterns, specifically the formation of submicrometer-size whirlpools.
Main Results:
- An anomalous (negative) voltage drop was detected, indicating the formation of electron whirlpools.
- The viscosity of graphene's electron liquid was measured to be approximately 0.1 m²/s, significantly higher than honey.
- Results align with predictions from many-body theory.
Conclusions:
- The study provides compelling evidence for electron hydrodynamics in graphene.
- Graphene's electron liquid exhibits measurable viscosity, offering a platform for studying these phenomena.
- This research demonstrates the potential for exploring electron hydrodynamics in high-quality graphene samples.
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