Stopping of energetic argon cluster ions in graphite: Role of cluster momentum and charge

We show that the implantation depth for argon clusters in graphite scales linearly with cluster momentum. A plot of implantation depth versus the momentum scaled with the projected surface area of the cluster falls on the same universal plot as that shown for semiconductor and metallic clusters, thus providing a universal scaling law for cluster implantation. Molecular dynamics simulations provide some insight to the mechanisms behind the empirical observation.