Dependence of ion channeling on relative atomic number in compounds

Ion channeling is a well-known radiation effect, important for understanding the passage of energetic ions and recoils in all crystalline materials. Recently we developed molecular dynamics and theory-based approaches to calculate ion channeling systematically over all crystal directions, providing ion 'channeling maps' that easily show in which directions channeling is expected [Nordlund et al., Phys. Rev. B. 94, 214109 (2016)]. As an extension of this work, which only considered pure elements, we consider here ion channeling in compounds. To obtain a comprehensive understanding of the effect of varying atom sizes on ion channeling, we compare compounds with pure elements of the same crystal structure, where the atomic number (nuclear charge) of the element is the average of that of the ions in the compound. The results show that the channeling effects in the compounds are very similar to the corresponding pure element, except if there is a really large ($\gtrsim 10$) ratio of atomic numbers. The reasons to this are discussed in terms of channeling theory.