Total energy calculations of missing dimer reconstructions on the silicon (001) surface

Abstract

Total energy pseudopotential calculations of missing dimer reconstructions on the Si(001) surface are presented. The authors have calculated the energy of the ideal unreconstructed surface and the energy of the (2*1) symmetric dimer, the (2*4) single missing dimer, the (2*2) single missing dimer and the (2*4) double missing dimer reconstructions. Their calculations give the (2*1) symmetric dimer reconstruction as the lowest energy surface of those considered. The double missing dimer reconstuction is very high in energy. The energy cost of removing one line of dimers in every four to form a (2*4) single missing dimer reconstruction is only 0.28 eV per dimer removed. Thus single missing dimer defects are either low-energy structural excitations or possibly a feature of the ground state of the silicon (001) surface.