Nanostructures induced by highly charged ions on CaF2 and KBr

Impact of a highly charged ion upon a solid surface can induce dramatic changes in the morphology only by the release of its potential energy. Hillocks and mono-atomic deep pits have been observed on the surfaces of CaF2 and KBr, respectively. For both processes a threshold in the potential energy exists for the creation of these nanostructures. Above this threshold the structure size increases linearly with potential energy. The mechanisms for the formation of hillocks and pits are discussed and a rst attempt to present a unied microscopic picture is made.