Stereographic intensity projections of elastically backscattered electrons in directional elastic peak electron spectroscopy: Experiment and theory

The stereographic intensity projections of elastically backscattered electrons for Au(1 1 1) were obtained by using directional elastic peak electron spectroscopy (DEPES). An enhancement of the recorded signal is observed when primary electrons with energies ranging from 0.5 to 2.0 keV strike the crystalline sample along the close-packed rows of atoms, proving the sensitivity of DEPES to the short atomic chain axial order. Besides, the obtained data reveal the threefold symmetry of the substrate. Experimental data are compared with the results of single scattering cluster (SSC) and multiple scattering (MS) calculations by means of contrast and an R-factor analysis. A satisfactory agreement between experiment and theory is found when the third scattering order is taken into account in MS approximation.