Structural and Electronic Properties of Clean and Hydrogenated Diamond (100) Surfaces

The structural and electronic properties of clean and hydrogenated diamond (100) surfaces have been investigated via fully self-consistent ab initio calculations. We find that the clean and the monohydrogenated surfaces reconstruct via the formation of rows of symmetric dimers. Further hydrogenation to a coverage of 1.5 monolayers stabilizes a surface with a (1 × 1) periodicity in the C layers, albeit with a low H-desorption energy for the formation of the reconstructed monohydride surface. The electronic properties of the surfaces have been calculated. Surface states within the bulk gap are found for the clean surface and for the strongly hydrogenated surface, but not in the monohydride case.