Influence of electronic stopping on sputtering induced by cluster impact on metallic targets

Abstract

Using molecular-dynamics simulation, we model the sputtering of a Au ͑111͒ crystallite induced by the impact of Au 13 projectiles with total energies up to 500 keV. Due to the uncertainty of the electronic stopping of Au moving in particular at small velocities, we performed several simulations, in which the electronic stopping parameters are systematically changed. Our results demonstrate the dominating influence of the cut-off energy E c , below which the high-velocity electronic stopping of atoms is switched off in the simulation. If E c is smaller than roughly one half the cohesive energy of the target, sputtering ceases after a few ps; the spike contribution to sputtering ͑also called phase explosion or gas-flow contribution͒ is entirely quenched and the sputtering yield is up to an order of magnitude smaller than when electronic stopping is taken into account only at higher atom energies. Our results demonstrate the importance of a careful modeling of electronic stopping in simulations of spike sputtering from metals.

Classical molecular dynamics simulations of hypervelocity nanoparticle impacts on amorphous silica

“…For smaller clusters and metallic targets, the correct vanishing threshold for the electronic stopping could be important in MD simulations. 34 In our simulations, the electronic stopping was switched off for at-oms having kinetic energies less than 5 eV. We expect that this is a reasonable approximation for the threshold, because the electronic stopping does not very much affect the outcome of large cluster impact at this energy regime.…”

Stopping of energetic cobalt clusters and formation of radiation damage in graphite

“…Electronic stopping was applied to all atoms that had kinetic energies higher than 5 eV. Test simulations show that the strength and threshold for the electronic stopping effect 31 does not significantly influence the results in this case.…”

Sputtering of a metal nanofoam by Au ions

“…At these low impact energies, the influence of electronic stopping is only minor; therefore no electronic stopping has been applied. The influence of the electron-phonon coupling on the quenching of the spike generated by the impact may be important [15]. However, the electronic heat conduction in foamy structures is changed with respect to that in compact materials [16,17]; this makes the correct inclusion of electronic effects during the spike phase a complex task.…”