Random and ordered defects on ion-bombarded Si(100)-(2×1) surfaces

Scanning tunneling microscopy STM images of Si(100)-(2×1) surfaces bombarded by low-dose 3-keV ${\mathrm{Ar}}^{+}$ ions showed random defects which ordered into line defects perpendicular to the dimer rows upon annealing at elevated temperatures. Molecular-dynamics simulations were performed to explain the shapes and sizes of the observed random defects and also to examine the stability of ordered defects. Our simulations showed good agreement with STM observations.