MANIFESTATIONS OF ELECTRONIC CORRELATIONS IN THE DIFFRACTION OF ELECTRON PAIRS FROM CRYSTALS

The energy-sharing spectra of correlated electron pairs ejected from C u(001) and Fe(110) surfaces reveal characteristic structures associate d with diffraction of the pair from the lattice. It is demonstrated th eoretically and experimentally that (1) the momentum-space positions o f these new features are determined by the change of the center-of-mas s wave vector of the pairs as compared to the reciprocal lattice vecto r, and (2) the relative intensities of the peaks and the shapes of the individual peaks are dependent on the internal correlation of the pai rs. Possible pathways for the pair creation are envisaged at various d iffracted beams.