Ab initio calculations of the H-induced surface restructuring on beta-SiC(0011)-(3x2)

The effect of H passivation on the ?-SiC(0 0 1)-(3×2) surface has been investigated for different hydrogen coverages with first principles pseudopotential calculations. Monohydride configurations result in symmetric Si addimers, while an asymmetric canted geometry is stabilized for dihydride coverages. Energy comparisons in the grand-canonical frame indicate that the occurrence of the actual hydride geometry strongly depends on the experimental conditions. On the basis of calculated images, we predict that dihydride or monohydride configurations could be discriminated with STM investigations.