Abstract

We report high-resolution Compton profiles (CP's) of Al along the three principal symmetry directions at a photon energy of 59.38 keV, together with corresponding highly accurate theoretical profiles obtained within the local-density approximation (LDA) based band-theory framework. A good accord between theory and experiment is found with respect to the overall shapes of the CP's and their first and second derivatives, as well as the anisotropies in the CP's dEFined as differences between pairs of various CP's. There are, however, discrepancies in that, in comparison to the LDA predictions, the measured profiles are lower at low momenta, show a Fermi cutoff that is broader, and display a tail that is higher at momenta above the Fermi momentum. A number of simple model calculations are carried out in order to gain insight into the nature of the underlying 3D momentum density in Al and the role of the Fermi surface in inducing fine structure in the CP's. The present results when compared with those on Li show clearly that the size of discrepancies between theoretical and experimental CP's is markedly smaller in Al than in Li. This indicates that, with increasing electron density, the conventional picture of the electron gas becomes more representative of the momentum density and that shortcomings of the LDA framework in describing the electron correlation effects become less important.

Notes

Originally published in Physical Review B v.62 (2000): 16528-16535. DOI: 10.1103/PhysRevB.62.16528

Keywords

Compton profiles, local-density approximation, Al, Fermi momentum

Subject Categories

Scattering (Physics), Symmetry (Physics)

Disciplines

Physics

Publisher

American Physical Society

Publication Date

12-15-2000

Rights Information

Copyright 2000 American Physical Society.

Rights Holder

American Physical Society

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