Burrowing of Co nanoparticles on clean Cu and Ag surfaces

Metal nanoparticles can display a unique behavior when deposited on substra tes with a significantly lower surface energy. Co nanoparticles in the 10 n m size regime burrow into clean Cu(100) and Ag(100) substrates when deposit ed at 600 It and also assume the substrate orientation. Deposition at room temperature fails to show either burrowing or reorientation. Crucial in und erstanding these results are the capillary forces and surface tension assoc iated with a nanoparticle: they must be high enough to drive atoms away fro m underneath the cluster.