A systematic study was made of the reconstruction of the Si(100) surface, based upon total energies calculated within the framework of the local-density approximation. Attention was focussed upon the extent to which total energy differences could be calculated reliably, by examining these differences for the ideal surface and 4 proposed reconstructions: p(2 x 1) symmetrical, p(2 x 1) asymmetrical, p(2 x 2) and c(4 x 2). The calculations were performed using norm-conserving pseudopotentials and a plane-wave basis. The convergence of the total energy differences was assessed by varying the energy cut-off used to truncate the plane-wave basis and the number of sampling points used to perform Brillouin zone integrals over a large range. The effect of optimizing atomic geometries as a function of the energy cut-off and the density of Brillouin zone sampling points was determined. With the exception of the p(2 x 2) and c(4 x 2) reconstructions, whose energies differed by only 3meV per dimer, it was possible to determine unambiguously the energy ordering of the 5 systems studied. Disagreements between previous calculations could be understood largely in terms of the differing energy cut-offs and Brillouin zone samplings used.

Theoretical Study of the Si(100) Surface Reconstruction. A.Ramstad, G.Brocks, P.J.Kelly: Physical Review B, 1995, 51, 14504-23