A New Direct Surface Structural Probe: Inversion Of Measured Kikuchi Electron Patterns

The technique of electron-emission holography (EEH) is reviewed with respect to its potential as a direct local structural probe. Direct inversion of the measured Kikuchi electron patterns is emphasized. The description of how the multiple scattering effects are eliminated by the integral-energy phase-summing method is presented. High-fidelity, artifact-free three-dimensional atomic images obtained by inverting simulated diffuse LEED and photoelectron diffraction patterns are shown. Direct inversion of the measured Kikuchi patterns shows clear images of the neighboring atoms within the range of the electron mean free path, thus yielding structural information with high resolution (~1 Å) in all directions. Special attention is paid to the correct role of background subtraction in removing artifacts, and to the selection of minimal experimental data in the practical application of EEH. Moreover, direct inversion of diffraction patterns from many different local emitters is found to yield a three-dimensional Patterson function of the near-surface structure. This leads to direct surface structural determination by inverting Kikuchi electron patterns. Finally, the future of this direct method based upon inverting Kikuchi electron patterns, including the comparison with diffuse LEED and photoelectron holography, is discussed.