An extensive computational study was made with the aim of investigating the nature of the ground-state geometry of the Si(001) surface. Analyzed for the first time in detail were possible sources of error which could arise in any correlated calculation for the system size considered. A detailed analysis was made of the cluster model of the surface. Estimates were made of the errors arising from the use of pseudopotential, finite cluster size, and method-dependent choice of ground-state geometry. The resultant error was estimated to be comparable to the energy scale. However, the energy variation due to negative thermal expansion at low temperatures was found to be qualitatively consistent with dimer symmetrization.

Ground-State Reconstruction of the Si(001) Surface - Symmetrical versus Buckled Dimers. P.Bokes, I.Stich, L.Mitas: Chemical Physics Letters, 2002, 362[5-6], 559-66