Au sputtering by cluster bombardment: A molecular dynamics study

Sputtering of a Au (1 1 1) surface induced by Au_n cluster bombardment is studied by molecular dynamics simulation, aiming at statistically representative results for larger clusters. Both equi-velocity Au_n (n=1,2,4) clusters at energy E/n=16 keV/atom and equi-energy clusters (n=1,2,4,8,12) with E=16 keV are used as projectiles. We observe: huge sputter yields, displaying a strong dependence on cluster size and energy; late sputter emission (beyond 30 ps after cluster impact); an increasing percentage of sputtered clusters for large sputter yields; the formation of large craters; a narrowing of the sputter-yield distributions for large clusters. In a sensitivity study, we show that the equilibrium interatomic potential has a strong influence on the sputter yield.