Three-dimensional electron momentum density of aluminum by (gamma,e gamma)spectroscopy

We report on the measurement of the three-dimensional electron momentum den sity (EMD) of aluminum. 150 keV photons with an intensity of 2 x 10(11) pho tons/s from a multipole wiggler of the European Synchrotron Radiation Facil ity have been scattered at a 100 nm thin self-supporting aluminum foil and measured in coincidence with their recoil electrons. To improve the agreeme nt with a full potential linear muffin-tin orbital theory, electron correla tion effects have been incorporated via the so-called Lam-Platzman correcti on [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 th ese experiments, we used the first derivative of the EMD as an indication o f the Fermi breaks. [S0163-1829(99)13115-1].