Si(0 0 1)/In-4×3 surface: a first principles total energy calculation

The atomic geometry and the energetics of the In-induced Si(0 0 1)-4×3 surface have been investigated using first-principles total energy calculations. We have studied two distinct 4×3 reconstructions which have been proposed recently based on experimental results. The first one is formed from the 4×1 phase with the formation of In–Sidimer–In structures [Phys. Rev. B 57 (1998) 12492]. The other one is characterized by the formation of In–Si–In mixed trimer on the surface [Appl. Surf. Sci. 123/124 (1998) 104]. We have determined the equilibrium surface atomic geometry starting from the two models proposed, and particularly for the trimer model, the atomic geometry is in good agreement with the X-ray diffraction studies. The calculated total energy difference between these two structures indicates that the trimer model is energetically more stable.