On the local density dependence of electronic stopping of ions in solids

• Published in: Journal of nuclear materials Vol. 507; pp. 258 - 266
• Main Authors: Caro, M., Tamm, A., Correa, A.A., Caro, A.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.08.2018; Elsevier BV; Elsevier
• Subjects: Adiabatic; ATOMIC AND MOLECULAR PHYSICS; Atomic collisions; Binary collisions; Channeling; Computer simulation; Crystals; Density dependence; Density functional theory; Electron gas; Electronic stopping power; Gases; Ions; Jellium; Molecular dynamics; Nickel; Quantum mechanics; Quantum physics; Simulation; Time dependence; Time dependent density functional theory; Electronic stopping power; Time dependent density functional theory; Nickel; Binary collisions
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2018.04.019

We use time-dependent density functional theory to calculate the electronic stopping Se in binary Ni-Ni atomic collisions and for a Ni projectile along channeling directions in a Ni crystal. Our results show that when Se is reported as a function of the ground state target electronic density ρ0 the stopping is not a single-valued function of the local density, as assumed in formalisms that date back to the origins of quantum mechanics, but shows loops, suggesting that it is inaccurate to model stopping as a dissipative force of the type F=β(ρ0)v, as it is customarily done in non-adiabatic molecular dynamics simulations of ion-solid interactions. We compare our results with Se in a uniform electron gas where the above definition for the force holds, and conclude on the validity of using jellium as a crude approximation for more realistic inhomogeneous electron gases. •The relation between stopping power and electronic density is multivalued.•Unperturbed host electronic density is not a good descriptor for stopping power.•Ab initio instantaneous Nickel stopping power in the non-adiabatic framework.•Time-Dependent Density Functional gives invaluable input to classical simulations.