Molecular dynamics study on stopping powers of channeled He and Li ions in Si

摘要

A molecular dynamics simulation method for calculating the electronic stopping power for MeV energy He and Li ions in crystalline silicon is described. Two methods for calculating electronic stopping in channelling directions are studied. In the first method velocity dependent phase-shifts are calculated using a spherical average of a doping atom potential moving in an electron gas. In the second method an interpolation scheme between the density functional theory-calculation for low energies and a Bethe-like formula for high energies is used. The methods have been used to calculate stopping powers for He ions impinging in channeling directions of crystalline Si up to 3 MeV. The interpolation model has also been used to calculate channeling stopping power for Li ions up to 9 MeV. The simulation results are compared with recent experiments.