Direct observation of ion-induced self-organization and ripple propagation processes in atomistic simulations

Patterns on sand generated by blowing winds are one of the most commonly seen phenomena driven by such a self-organization process, as has been observed at the nanoscale after ion irradiation. The origins of this effect have been under debate for decades. Now, a new methodology allows to simulate directly the ripple formation by high-fluence ion-irradiation. Since this approach does not pre-assume a mechanism to trigger self-organization, it can provide answers to the origin of the ripple formation mechanism. The surface atom displacement and a pile-up effect are the driving force of ripple formation, analogously to the macroscopic one. IMPACT STATEMENT The presented model allows to follow the ripple formation and propagation in different steps, at the atomic level, for the first time under low irradiation energies.