Anisotropic vacancy kinetics and single-domain stabilization on Si(100)-2×1

Preferential annihilation of mobile surface vacancies at the ends, rather than the sides, of dimer rows leads to a new, nonequilibrium, single-domain phase of Si(100) that is not accessible by epitaxial growth, but is stable at moderate temperatures (T{~}450 ^∘{}C). These results emerge from a tunneling-microscope study of layer-by-layer removal of Si from Si(100) under 225-eV Xe-ion bombardment.