Electronic stopping in ternary material SiCN: Anomalous behavior of slow channeling helium ions

Abstract

By performing time-dependent density functional theory simulations, we reveal an anomalous deviation from linear low-velocity electronic stopping for slow channeling helium ions in the ternary material SiCN. We ascribe the deviation behavior that occurs upon helium ion irradiated SiCN to trapped electrons in the final stage of collision. The result show that the electron trapping for the exit-side of the material is more sensitive to the projectile velocity than that for the entrance-side, and that this has a corresponding relationship with nonlinear electronic stopping. In addition, our calculations reveal enhanced nonlinear electronic stopping to the off-center channels, particularly near the C/N layers. We propose the increased electron excitation for the increased charge density channel under a small impact parameter as the most plausible explanation for this behavior.