Measuring Hall Viscosity of Graphene's Electron Fluid

Understand

Materials subjected to a magnetic field exhibit the Hall effect, a phenomenon studied and understood in fine detail.

• Here we report a qualitative breach of this classical behavior in electron systems with high viscosity.
• The viscous fluid in graphene is found to respond to non-quantizing magnetic fields by producing an electric field opposite to that generated by the classical Hall effect.
• The viscous contribution is large and identified by studying local voltages that arise in the vicinity of current-injecting contacts.