Probing Hydrodynamic Materials from First Principles*

In the hydrodynamic regime of transport, momentum-conserving scattering dominates momentum-relaxing processes such as Umklapp, defect, and boundary scattering so that momentum is quasi-conserved and electron flow obeys the formalism of hydrodynamics. In light of recent experimental evidence of hydrodynamic transport in PdCoO2, WP2, and PtSn4, understanding the specifics of microscopic scattering processes in these materials is of fundamental interest. In order to provide a more comprehensive perspective of experimentally observed hydrodynamic phenomena, we use first-principles methods including calculations of electron-phonon coupling to evaluate a number of different scattering lifetimes, the electrical and thermal conductivities, and optical properties of these materials. Through our ab initio framework, we aim to to probe the microscopic properties of the recently experimentally observed hydrodynamic solids and study the interplay between topological physics and ultrafast dynamics in these materials.