IMAGING OF A SURFACE ALLOY WITH ENERGY-DEPENDENT PHOTOELECTRON HOLOGRAPHY

Fourier transformation of experimental energy-dependent photoelectron diffraction data has been used to produce an essentially artifact-free image of a surface alloy. This direct method, based upon the intersection off contour arcs associated with each measurement direction, can provide vectorial atomic positions with atomic resolution. A rapid data collection mode was introduced. Surface structural sensitivity was confirmed by comparison with multiple-scattering simulations. The previously ambiguous surface geometry of c(2x2)Au/Cu(001) has been determined, with clear, non-model-dependent discrimination of the surface alloy over the overlayer structure.