Electron Viscosity, Current Vortices and Negative Nonlocal Resistance in Graphene

Understand

Quantum-critical states of diverse strongly correlated systems are predicted to feature universal collision-dominated transport resembling that of viscous fluids.

• However, investigation of these phenomena has been hampered by the lack of known macroscopic signatures of the hydrodynamic regime at criticality.
• Here we identify vorticity as such a signature and link it with an easily verifiable striking macroscopic transport behavior.
• Produced by the viscous flow, vorticity can drive electric current against an applied field, resulting in a negative nonlocal voltage.