Electron and ion dynamics in materials after particle radiation and optical excitation

Quantum states of matter are tied to the interplay of interactions in the Hamiltonian and novel states can emerge in materials depending on the relative coupling strength, e.g. between electronic and lattice degrees of freedom as well as coupling to external fields. Fabricating and processing novel materials for electronic devices with nanoscale dimensions requires extremely precise techniques with control at the atomic level. In addition, characterizing and probing properties, e.g. via electronic and optical excitations, require knowledge about a material on ultrafast time scales. In this talk I will present recent quantum-mechanical first-principles predictions for electron dynamics and the subsequent ionic motion that follows after an initial excitation of the electronic system in semiconductors and metals. In particular, we showed that long-lived electronic excitations in proton irradiated MgO can facilitate diffusion of oxygen vacancies. For silicon material under swift heavy ion irradiation, we analyzed the charge state dynamics of the projectile ion and used it to explain electronic stopping behavior. Finally, for proton and laser irradiated aluminum surfaces, we quantify electron emission, projectile charge capture, and pre-equilibrium electronic stopping behavior, that is unique to thin films and two-dimensional materials. Limitations and possible extensions of the theoretical description, including the bridging of multiple time or length scales, will be included in the discussion.