Lattice mismatch dislocations in a preferentially sputtered alloy studied by scanning tunneling microscopy

Scanning tunneling microscopy (STM) on a sputtered and annealed ${\mathrm{Pt}}_{25}$${\mathrm{Ni}}_{75}$(111) single crystal reveals a network of subsurface lattice mismatch dislocations caused by platinum enrichment due to preferential sputtering and recoil mixing. Atomically resolved STM topographs are compared with simulations of these dislocations using embedded atom potentials. This allows one to estimate the depth of the dislocations, and thus the thickness of Pt enrichment, which is three monolayers on the 500 eV ${\mathrm{Xe}}^{+}$ sputtered and five monolayers on the ${\mathrm{Ar}}^{+}$ sputtered surface, compatible with the depth of radiation damage.