We have used the ensemble Kohn-Sham method with the local-density approximation to determine self-consistently the dynamic screening cloud around an impurity moving adiabatically through a uniform electron gas with velocity below the Fermi velocity. The asymmetry of the induced field and electronic density caused by the impurity motion is fully taken into account. We discuss the forward-backward asymmetry for the case of bare positive and negative charges as well as for hydrogen atoms. We show that the stopping power of the electron gas varies linearly with the projectile velocity up to velocities close to the Fermi velocity. We study the asymmetry of the bound states, its contribution to the stopping power and the evolution of the binding energy as a function of projectile velocity. Finally, we give a complete derivation of the low energy behavior of the stopping power and the generalization of the Friedel sum rule and oscillations for the case of moving impurities.

• Received 22 June 1998

DOI:https://doi.org/10.1103/PhysRevB.59.2537