Behavior of Weyl Semimetals in the Hydrodynamic Electron Transport Regime

In solid state transport regimes where electron-electron scattering dominates over impurity scattering and other momentum-relaxing processes, electron flow is governed by the laws of hydrodynamics. This leads to a variety of surprising behaviors in different materials, such as breakdown of the Wiedemann-Franz law, appearance of electron vortices in graphene, and tunable viscosity via magnetic field in a Weyl semimetal. Here we report a new microscopic model of this behavior using a combination of ab initio scattering and transport methods and fluid dynamics techniques. Our work establishes a connection between the observed hydrodynamic phenomena in Weyl semi metals and their crystal structure and symmetry.