Progress towards describing electron hydrodynamics from first principles

Electron-electron (e-e) interactions are an important mechanism for electron scattering in pure materials at low temperatures. When momentum-conserving e-e scattering takes place at a larger rate than momentum-relaxing scattering processes, such as electron-phonon and electron-defect scattering, then the material is said to enter the hydrodynamic transport regime. This regime gives rise to novel transport behaviors, including a decrease in resistivity with temperature, as well as viscous electron flow. In this talk, we show progress toward tackling hydrodynamic flow with quantitative first-principles methods. We present calculations of e-e interactions, scattering rates, and e-e limited transport properties for both bulk and 2D materials. To obtain these results, we interpolate the screened Coulomb interaction on a fine momentum grid using maximally-localized Wannier functions, and generalize the Boltzmann equation solvers in the PERTURBO package to include e-e scattering. These efforts pave the way for studies of hydrodynamic transport in both conventional metals and novel quantum materials.