Diffraction Patterns in the Specimen-Current Image of a Single Crystal at Low Beam Energies

With use of low-energy electrons (40-400 eV) to scan single crystals of aluminum, diffraction patterns were discovered in the specimen-current images. The patterns have the symmetry of the reciprocal lattice and appear to be related to peaks in the curves of low-energy electron-diffraction intensity versus incident angle for a specified primary beam energy. These patterns provide a means to investigate surface phenomena.