Electron hydrodynamics in graphene antidot superlattices

Electron hydrodynamics is a transport regime where the electrons behave like a fluid. Experimental realizations of viscous electron flow have multiplied with ultrapure materials, such as graphene, GaAs heterostructures, or PdCoO2. The electron’s viscosity only reveals itself in geometrically engineered devices, so we fabricate a graphene antidot superlattice. It exhibits superballistic conduction, where electron-electron collisions reduce the resistance below the ballistic limit. We study magnetotransport and find an intermittent superballistic effect that classifies ballistic and collective transport, supporting previous predictions. Simulations of the Navier-Stokes and the Boltzmann equation in arbitrary geometries give insight into edge scattering, tomographic dynamics, and the generalization to anisotropic materials. Last, we discuss potential applications of electron hydrodynamics, for low-dissipation devices or high-frequency oscillating circuits. In conclusion, hydrodynamics is the equivalent of Ohm’s law for many 2D devices, and the antidot superlattice is a convenient geometry to turn a material into a meta-material with a hydrodynamic response.