Dynamics of ballistic photocurrents driven by Coulomb scattering

First principles real-time time dependent density functional theory (rt-TDDFT) calculations reveal the existence of ballistic photocurrents generated by Coulomb scattering. These currents arise in non-equilibrium contexts under high fields. With monolayer GeS as an example, it is predicted that ballistic currents can exceed shift currents under experimentally accessible conditions. Moreover, these simulations reveal recombination pathways that work to modify shift current magnitudes beyond perturbation theory predictions.