Three-dimensional electron momentum density of aluminum by(γ,eγ)spectroscopy

Abstract

We report on the measurement of the three-dimensional electron momentum density (EMD) of aluminum. 150 keV photons with an intensity of $2\ifmmode\times\else\texttimes\fi{}{10}^{11}$ photons/s from a multipole wiggler of the European Synchrotron Radiation Facility have been scattered at a 100 nm thin self-supporting aluminum foil and measured in coincidence with their recoil electrons. To improve the agreement with a full potential linear muffin-tin orbital theory, electron correlation effects have been incorporated via the so-called Lam-Platzman correction [Phys. Rev. B 9, 5122 (1974)]. A comparison with two-dimensional angular correlation of annihilation radiation has been made and demonstrates the strong influence of the positron wave function on the EMD. In analogy to these experiments, we used the first derivative of the EMD as an indication of the Fermi breaks.