The 2 × 1 structural reconstruction of Si{001}

New data and LEED (low-energy electron diffraction) intensity analysis have led to a new structure for Si{001} 2 × 1 which gives very satisfactory agreement with the data; the fit to experiment is substantially better than for any previous structure. The structure has a dimer bond length of 2.54 Å, an average contraction of the first layer spacing of 8%, three kinds of asymmetric displacements of the two dimer atoms, and differs substantially from all other recently proposed structures. © 1982.