Molecular dynamics simulation of atom ejection from the (0001) surface of single crystal zirconium due to keV ion bombardment Available to Purchase

Atom desorption from the (0001) surface of a HCP single crystal Zr induced by 2 keV Ne⁺, Ar⁺, and Xe⁺ ions at four incident angles is studied using molecular dynamics simulations. The atom ejection pattern for normal ion incidence has six approximately equal intense spots around a weak central spot, in agreement with the pattern observed experimentally. Few surface atoms have a high probability of being sputtered and they contribute significantly to the formation of the intense spots. The mechanism for the formation of the spots is determined primarily by the first two layers of the crystal and knock‐on sputtering by primary recoil is important for all three ions. The relative importance of primary recoil knock‐on ejection increases with ion mass. Other mechanisms involve momentum transfer through second layer atoms. The Lehmann–Sigmund mechanism is not applicable for the ion masses and energies used in the simulations. Similarities and differences between the HCP (0001) and FCC (111) surfaces are discussed and it is proposed that, to a certain extent, the atom ejection mechanisms described in this paper may also apply to FCC (111) surfaces under similar sputtering conditions.