Fermi surface signatures in the compton profile of Be

• Published in: The Journal of physics and chemistry of solids 1998, Vol.59 (1), p.99-103
• Main Authors: Itou, M., Sakurai, Y., Ohata, T., Bansil, A., Kaprzyk, S., Tanaka, Y., Kawata, H., Shiotani, N.
• Format: Article
• Language: English
• Subjects: Applied sciences; beryllium; Compton profile; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron states; Exact sciences and technology; Fermi surface; Fermi surface: calculations and measurements; effective mass, g factor; KKR method; local density approximation; Metals. Metallurgy; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Other interactions of matter with particles and radiation; Physics; synchrotron radiation; X-ray scattering
• ISSN: 0022-3697; 1879-2553
• DOI: 10.1016/S0022-3697(97)00146-7

We report high-resolution Compton profiles of two single crystals of Be with surface normals oriented along the [0001] and [112̄0] directions. The results are compared and contrasted with corresponding, highly accurate all-electron computations based on the band theory framework within the local-density approximation (LDA). A reasonable overall level of agreement is seen between theory and experiment with respect to the shapes of the Compton profiles, as well as the Fermi-surface-induced finer structure in the first and second spectral derivatives. However, the measured profiles are lower than theory at low momenta, clearly displaying broadened Fermi surface features compared with the theoretical predictions, and point to the importance of electron correlation effects beyond the LDA for a proper description of the momentum density. The aforementioned similarities and differences between theory and experiment in Be are rather like the situation that has been observed in recent high-resolution Compton studies of other materials.