Abstract:
Recent scanning tunnelling microscopy and spectroscopy (STM/STS) observations show that the C-defects , which are commonly observed on the Si(001)surface , act as nucleation centres for metal atoms diffusing on this substrate. These measurements indicate that metal atoms deposited on Si(001) tend to form chains pinned to the defects. These experimental results strongly suggest that the presence of C-defects increases considerably the local chemical reactivity of the silicon substrate. In this talk the results of the theoretical study related to this problem, based on the ab-inito density functional theory (DFT) calculations, will be presented and discussed. The aim of this study is to determine the mechanism responsible for the strong reactivity of C-defects and the formation of the one-dimensional structures in the front of the defects by the diffusing adatoms. The obtained theoretical results will be analysed in the context of the existing STM/STS data.