Unsaturated cyclic-hydrocarbon molecules on a Si(0 0 1) surface: A first-principles approach

Chemisorption of unsaturated cyclic-hydrocarbon molecules C6H10, C6H8 and C5H8 on Si(0 0 1) clean surface was investigated based on first-principles calculations, and the adsorption structures were discussed in comparison with the experimental data. As for C6H10, two kinds of stable conformation were determined, which are consistent with two types of characteristic STM images and spectroscopic data. On the other hand, we also found two kinds of adsorption structures for C6H8 molecules, but the structure supported by STM and UPS observations is slightly unstable compared with the other one, and the situation is still mysterious.