Evidence for local spots of viscous electron flow in graphene at moderate mobility

Abstract

Dominating electron-electron scattering enables viscous electron flow exhibiting hydrodynamic current density patterns such as Poiseuille profiles or vortices. The viscous regime has recently been observed in graphene by non-local transport experiments and mapping of the Poiseuille profile. Here, we probe the current-induced surface potential maps of graphene field effect transistors with moderate mobility using scanning probe microscopy at room temperature. We discover micron-sized large areas appearing close to charge neutrality that show current induced electric fields opposing the externally applied field. By estimating the local scattering lengths from the gate dependence of local in-plane electric fields, we find that electron-electron scattering dominates in these areas as expected for viscous flow. Moreover, we suppress the inverted fields by artificially decreasing the electron-disorder scattering length via mild ion bombardment. These results imply that viscous electron flow is omnipresent in graphene devices, even at moderate mobility.

89 pages, 24 figures, published in Nano Letters

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• Imaging the breaking of electrostatic dams in graphene for ballistic and viscous fluids
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• Driving Viscous Hydrodynamics in Bulk Electron Flow in Graphene Using Micromagnets
• Anomalous Gurzhi effect
• Viscous flow through a finite-width slit: Boundary conditions and dissipation
• Hydrodynamics of the electronic Fermi liquid: a pedagogical overview
• Two-dimensional hydrodynamic electron flow through periodic and random potentials
• Pseudo-hydrodynamic flow of quasiparticles in semimetal WTe2 at room temperature
• Viscoelastic tensor and hydrodynamics of altermagnets
• Resolving the Corbino Shockley-Ramo Paradox for Hydrodynamic Current Noise
• Viscoelastic response and anisotropic hydrodynamics in Weyl semimetals
• Relativistic Wind Farm Effect: Possibly Turbulent Flow of a Charged, Massless Relativistic Fluid in Graphene