Sputtering of Au (111) induced by 16-keV Au cluster bombardment: Spikes, craters, late emission, and fluctuations

Sputtering of a Au (111) surface induced by 16-keV Aun cluster bombardment (n=1,2,4,8,12) is studied by molecular-dynamics simulation. A statistically significant picture of the materials effects induced is obtained: With the exception of Au1 bombardment, sputtering lasts at least 8 ps, a pronounced crater is formed as a rule, and large clusters emitted late from the crater rim contribute substantially to sputtering. Sputter yield and crater size are strongly positively correlated in each individual impact event. For larger-cluster impact (n≥4), fluctuations in these two quantities shrink, giving the events a macroscopic appearance