Ab initio calculations of the H-induced surface restructuring on beta-SiC(001)-(3 x 2)

The effect of H passivation on the beta -SiC(0 0 1)-(3 x 2) surface has bee n investigated for different hydrogen coverages with first principles pseud opotential calculations. Monohydride configurations result in symmetric Si addimers. while an asymmetric canted geometry is stabilized for dihydride c overages. Energy comparisons in the grand-canonical frame indicate that the occurrence of the actual hydride geometry strongly depends on the experime ntal conditions. On the basis of calculated images, we predict that dihydri de or monohydride configurations could be discriminated with STM investigat ions. (C) 2001 Elsevier Science B.V. All rights reserved.