Can hydrogen stabilize the alpha-SiC(0001)root 3x root 3 surface?

The paper presents an analysis of the energetics of a few possible candidates for the structural model of the root 3 X root 3 R30 degrees reconstruction of the alpha-SiC(0001) surface. The analysis is based on the semi-empirical, self-consistent, quantum-mechanical cluster calculations of MNDO-type (AM1 parametrization). Clean stoichiometric, Si rich and C rich surface structures as well as surfaces saturated by hydrogen and the hydroxyl groups are examined and particular care is applied when comparing energies of the structures with different stoichiometries. The results confirm the claim that the most favorable model for the reconstruction is here the one where hydrogenated triangles of C atoms saturate the surface silicon dangling bonds. Moreover, the calculated energies indicate that the reconstructed surface is a result of the desorption of SiO from the 1 X 1 surface originally saturated by hydroxyl groups.