Comparison of electronic energy loss in graphene and BN sheet by means of time-dependent density functional theory

Time-dependent density functional theory combined with Ehrenfest dynamics are employed to calculate electronic energy loss of energetic ions in two-dimensional graphene and white graphene (BN) targets. Special attention is paid to the effects of different electronic structures on their stopping power. Our results show that the energy transferred to the graphene target is much larger than to BN for both H+ and He2+ projectiles. Since the energy is mainly deposited into the electronic degree of freedom, it means that the electronic structure of the target plays an important role in determining the collision process. Our analysis indicates that more excited electrons are observed in graphene compared to BN. At low energies, a velocity proportional relation is found in the electronic energy loss of H+ and He2+ in both graphene and BN. In particular, a threshold velocity is observed for He2+. Finally, we have compared the energy transfer from neutral and charged projectiles when they collide with graphene and BN and the results show that charged projectiles damage the targets more severely.