Study of high order reconstructions of the Si(100) surface

The structure of the reconstructed Si(100) surface is studied using the tight-binding energy minimization method combined with a renormalization-group calculation. (2×1), c(2×2), p(2×2), (4×1), c(4×2), and p(4×2) structures are studied and compared. They are classified into two groups which are separated by a large activation barrier. In one group, (2×1), p(2×2), and c(4×2) structures are almost degenerate in energy, which can result in diffuse (2×1) LEED patterns. In the other group, a second-order phase transition can occur from the c(2×2) to the disordered structure at ∼800 K. Domains of different structures may coexist on the actual surface.