Atomic fingers, bridges and slingshots: formation of exotic surface structures during ion irradiation of heavy metals

Recent experiments on ion irradiation of heavy metals such as gold and silver have shown that very unusual surface configurations can be produced by the irradiation. Typically, the surface damage has the shape of a crater, similar to those produced by meteorite impacts. The crater shapes are, however, often highly asymmetric and can show extended adatom ridges extending far from the crater well. Using molecular dynamics simulations we show how such exotic atom arrangements are produced. We describe atomic bridges over a crater and illustrate a slingshot-like effect which can propel atom clusters far from an impact position to produce isolated adatom islands.