“…When more than 5 ML Co is deposited, the surface becomes more cobalt rich than the initial CoSi 2 phase. According to Rangelov et al [5], as Co coverage increases, part of the Co atoms exist in a CoSi 2 -like environment while the rest forms a Co-Si solid solution with inter-diffusion of Co and Si atoms. Using low energy electron diffraction (LEED) and XPS, Derrien et al [6] found that when the Co coverage exceeds 2.0 ML, the LEED spot associated with Si(1 1 1)-(7 · 7) disappears and a Si(1 1 1)-(1 · 1) pattern forms.…”