Direct observation of vortices in an electron fluid
arXiv:2202.02798 · doi:10.1038/s41586-022-04794-y
Abstract
Vortices are the hallmarks of hydrodynamic flow. Recent studies indicate that strongly-interacting electrons in ultrapure conductors can display signatures of hydrodynamic behavior including negative nonlocal resistance, Poiseuille flow in narrow channels, and a violation of the Wiedemann-Franz law. Here we provide the first visualization of whirlpools in an electron fluid. By utilizing a nanoscale scanning superconducting quantum interference device on a tip (SQUID-on-tip) we image the current distribution in a circular chamber connected through a small aperture to an adjacent narrow current carrying strip in high-purity type-II Weyl semimetal WTe2. In this geometry, the Gurzhi momentum diffusion length and the size of the aperture determine the vortex stability phase diagram. We find that the vortices are present only for small apertures, whereas the flow is laminar (non-vortical) for larger apertures, consistent with the theoretical analysis of the hydrodynamic regime and in contrast to the expectations of ballistic transport in WTe2 at low temperatures. Moreover, near the vortical-to-laminar transition, we observe a single vortex in the chamber splitting into two vortices, a behavior that can occur only in the hydrodynamic regime and cannot be sustained by ballistic transport. These findings suggest a novel mechanism of hydrodynamic flow: instead of the commonly considered electron-electron scattering at the bulk, which becomes extremely weak at low temperatures, the spatial diffusion of charge carriers' momenta is enabled by small-angle scattering at the planar surfaces of thin pure crystals. This surface-induced para-hydrodynamics opens new avenues for exploring and utilizing electron fluidics in high-mobility electron systems.
arXiv commentMain text: 15 pages, 5 figures. Method: 18 pages, 9 Extended Data figures. Supplementary videos: 2
References in corpus (81)
- Titanic Magnetoresistance in WTe2
- Negative local resistance caused by viscous electron backflow in graphene
- Observation of the Dirac fluid and the breakdown of the Wiedemann-Franz law in graphene
- Evidence for hydrodynamic electron flow in PdCoO
- Scanning nano-SQUID with single electron spin sensitivity
- Superballistic flow of viscous electron fluid through graphene constrictions
- Electron Viscosity, Current Vortices and Negative Nonlocal Resistance in Graphene
- Imaging viscous flow of the Dirac fluid in graphene
- Hydrodynamic electron flow in high-mobility wires
- Measuring Hall Viscosity of Graphene's Electron Fluid
- Visualizing Poiseuille flow of hydrodynamic electrons
- Electrical and Thermal Transport at the Planckian Bound of Dissipation in the Hydrodynamic Electron Fluid of WP2
- Extremely high magnetoresistance and conductivity in the type-II Weyl semimetals WP2 and MoP2
- Quantum oscillations, thermoelectric coefficients and the Fermi surface of semi-metallic WTe2
- Non-local transport and the hydrodynamic shear viscosity in graphene
- Temperature induced Lifshitz transition in WTe2
- Nanoscale thermal imaging of dissipation in quantum systems
- Hydrodynamic description of transport in strongly correlated electron systems
- Higher-Than-Ballistic Conduction of Viscous Electron Flows
- Negative magnetoresistance in viscous flow of two-dimensional electrons
- Imaging of super-fast dynamics and flow instabilities of superconducting vortices
- Hydrodynamic Electron Flow and Hall Viscosity
- Fluidity Onset in Graphene
- Tuning Magnetotransport in a Compensated Semimetal at the Atomic Scale
- Self-aligned nanoscale SQUID on a tip
- Bulk and shear viscosities of the 2D electron liquid in a doped graphene sheet
- Imaging phonon-mediated hydrodynamic flow in WTe2
- Hall effect in the extremely large magnetoresistance semimetal WTe
- The boundary conditions of viscous electron flow
- Experimental observation of anisotropic Adler-Bell-Jackiw anomaly in type-II Weyl semimetal WTe crystals at the quasi-classical regime
- Fermi surface fluctuations and single electron excitations near Pomeranchuk instability in two dimensions
- Electron hydrodynamics dilemma: whirlpools or no whirlpools
- Scanning Gate Microscopy in a Viscous Electron Fluid
- Probing dynamics and pinning of single vortices in superconductors at nanometer scales
- Behavior of vortices near twin boundaries in underdoped
- Landau Quantization and Highly Mobile Fermions in an Insulator
- Pre-Turbulent Regimes in Graphene Flows
- Hydrodynamic-to-ballistic crossover in Dirac fluid
- Scanning superconducting quantum interference device on a tip for magnetic imaging of nanoscale phenomena
- Improved current density and magnetisation reconstruction through vector magnetic field measurements
- Mechanical control of individual superconducting vortices
- Control of electron-electron interaction in graphene by proximity screening
- Ballistic and hydrodynamic magnetotransport in narrow channels
- Vorticity induced negative nonlocal resistance in viscous two-dimensional electron system
- Hydrodynamic and ballistic transport over large length scales in GaAs/AlGaAs
- Linking Spatial Distributions of Potential and Current in Viscous Electronics
- Tomographic Dynamics and Scale-Dependent Viscosity in Two-Dimensional Electron Systems
- Magnetohydrodynamics in graphene: shear and Hall viscosities
- Viscosity of two-dimensional electrons
- SQUID-on-tip with single-electron spin sensitivity for high-field and ultra-low temperature nanomagnetic imaging
- Stokes flow around an obstacle in viscous two-dimensional electron liquid
- Hydrodynamic effects in interacting Fermi electron jets
- Particle Collisions and Negative Nonlocal Response of Ballistic Electrons
- Multiple Fermi pockets revealed by Shubnikov-de Haas oscillations in WTe2
- Hydrodynamic collective modes in graphene
- Dissipative and Hall viscosity of a disordered 2D electron gas
- Nonmonotonic magnetoresistance of a two-dimensional viscous electron-hole fluid in a confined geometry
- Anomalous Hydrodynamic Transport in Interacting Noncentrosymmetric Metals
- Turbulent hydrodynamics in strongly correlated Kagome metals
- Direct reconstruction of two-dimensional currents in thin films from magnetic field measurements
- Manifestations of classical size effect and electronic viscosity in the magnetoresistance of narrow two-dimensional conductors: Theory and experiment
- Viscous magnetotransport and Gurzhi effect in bilayer electron system
- Electron hydrodynamics of anomalous Hall materials
- Counterflows in viscous electron-hole fluid
- Superballistic electron flow through a point contact in a Ga[Al]As heterostructure
- Dynamo Effect and Turbulence in Hydrodynamic Weyl Metals
- Imaging anisotropic vortex dynamics in FeSe
- Vorticity of viscous electronic flow in graphene
- Prospects for the detection of electronic pre-turbulence in graphene
- Evidence for local spots of viscous electron flow in graphene at moderate mobility
- Beyond Ohm's law -- Bernoulli effect and streaming in electron hydrodynamics
- Imaging the breakdown of ohmic transport in graphene
- Correlation of Crystal Quality and Extreme Magnetoresistance of WTe
- Anti-Poiseuille flow in neutral graphene
- Stokes flow analogous to viscous electron current in graphene
- Rectification by hydrodynamic flow in an encapsulated graphene Tesla valve
- Conformal maps of viscous electron flow in the Gurzhi crossover
- An electron jet pump: The Venturi effect of a Fermi liquid
- Magnetic hallmarks of viscous electron flow in graphene
- Artificial electric field and electron hydrodynamics
- Heating of inhomogeneous electron flow in the hydrodynamic regime
Cited by in corpus (12)
- Imaging the breaking of electrostatic dams in graphene for ballistic and viscous fluids
- Visualizing bulk and edge photocurrent flow in anisotropic Weyl semimetals
- Universal behavior of highly-confined heat flow in semiconductor nanosystems: from nanomeshes to metalattices
- Non-linear Transport Phenomena and Current-induced Hydrodynamics in Ultra-high Mobility Two-dimensional Electron Gas
- Nonlocal conductivity, continued fractions and current vortices in electron fluids
- Para-hydrodynamics from weak surface scattering in ultraclean thin flakes
- Breaking down the magnonic Wiedemann-Franz law in the hydrodynamic regime
- Current Noise of Hydrodynamic Electrons
- Viscous flow through a finite-width slit: Boundary conditions and dissipation
- Heat transport in Weyl semimetals in the hydrodynamic regime
- Magnetic Imaging with High Spatial Resolution Using a Single Niobium-Nitride-Based Three-Dimensional Nanobridge Junction
- Tunable THz-whistle built on two-dimensional Helmholtz resonator