Hidrodinámica inducida por stress producido mediante irradiación iónica en materiales amorfizablesdinámica molecular y teoría

Laburpena

The motivation of this thesis is to solve the current lack of satisfactory theoretical explanations of nanopatterning of silicon by ion beam sputtering. During the last years, the current paradigm (the so-called Bradley-Harper theory) has been recognised unsuitable, and in some cases even contradictory, with new experimental data acquired during the last decade. In addition, numerical methods have been almost exclusively devoted to highly idealized cases, such as single ion impacts on perfectly crystalline targets, while real experiments consist in consecutive impacts on the irradiated target. We introduce a novel theoretical framework that accounts for the mentioned new experimental results and fills the gap between the macroscopic theoretical descriptions, based on partial differential equations, and the microscopic Molecular Dynamics (MD) results. This framework allows us to make a comparison with already published experiments and newly ones performed by a collaborating group. Thus, we arrive at the conclusion that ion induced stress is the single most important mechanism that predicts the emergence of ripple nanopatterning, the parameters controlling their size and the transition from flat to nanopatterned surfaces.