Speaker
Description
The slowing down of energetic charged ions in matter involves two contributions: the nuclear and electronic stopping powers. Although the nuclear stopping power can now be predicted with high accuracy [1], substantial uncertainties remain in the calculation of the electronic stopping power, especially below the Bohr velocity. These uncertainties are exacerbated by trajectory-dependent effects, such as channeling, whereby ions travelling along certain crystal directions may encounter atomic and electronic densities that are significantly below the average [2]. This presents challenges in predicting the effects of ion irradiation in nuclear, space, materials science, and microelectronics industries.
In this work, we present the implementation of a trajectory-dependent model for the electronic stopping power in the efficient molecular dynamics code MDRANGE. This model is dependent on the local electron density experienced by the ion, is parameter-free, and inherently trajectory-dependent [3]. We benchmark this implementation against ion ranges and directly measured energy losses from ion transmission experiments [4]. We further discuss how this model can mitigate the uncertainties in predicting energy losses, particularly in crystal channels, and how it provides genuine predictive capability in modelling the electronic stopping power.
This work enhances the accuracy of modelling electronic energy losses in ion-material interactions and presents an opportunity to significantly improve the fidelity of ion irradiation simulations.
[1] Peltola, J., et al. Radiat. Eff. Defects Solids 161.9 (2006): 511-521.
[2] Sillanpää, J., et al. Phys. Rev. B 62.5 (2000): 3109-3116.
[3] Tamm, A., et al. Phys. Rev. Lett. 120.18 (2018): 185501.
[4] Lohmann, S., et al. Phys. Rev. A 102.6 (2020): 062803.
