A chemical-specific photoelectron diffraction structure determination of a carbon rich buffer layer on SiC is reported. In addition to the long-range ripple of this surface, a local buckling in the hexagonal sublattice, which breaks the local range order symmetry, was unraveled.

We report a combined high-resolution photoemission (XPS) and photoelectron diffraction (XPD) investigation of the three layer system MgO/Fe/GaAs(001). Each layer is investigated with regard to its structure. The two dimers model of the GaAs (4 × 2) reconstruction was confirmed by XPD patterns. We find the intermediate Fe layer in a crystalline structure. Further, the study clearly shows a well-ordered epitaxial MgO film on Fe. A careful analysis of the interface signals indicates an interdiffusion at the Fe/GaAs interface and partially shifted magnesium layers at the MgO/Fe interface.