A Compton scattering study on the Hume-Rothery mechanism of AlCu–TM (TM: transition metal) quasicrystals

• Published in: Journal of physics. Condensed matter 2006-08, Vol.18 (31), p.7203-7208
• Main Authors: Okada, J T, Sakurai, Y, Watanabe, Y, Ishikawa, R, Yokoyama, Y, Hiraoka, N, Itou, M, Nanao, S
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Magnetic resonances and relaxations in condensed matter, mössbauer effect; Mössbauer effect; other γ-ray spectroscopy; Physics
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/18/31/015

The electron momentum distributions in icosahedral Al64Cu23Fe13, icosahedral Al63Cu23Ru13 and decagonal Al65Cu15Co20 quasicrystals have been studied using the high-resolution Compton scattering technique. The electron-per-atom ratios (e/a) of the quasicrystals were determined quantitatively for the first time from the Compton profiles. The radii of the Fermi spheres were evaluated from the values of e/a on the basis of the free-electron model. Comparisons between the radius of the Fermi spheres and the size of the quasi-Brillouin zones show that the icosahedral quasicrystals meet the empirical matching condition, while the decagonal quasicrystal does not do this so well. This implies that the Hume-Rothery mechanism works for the formation of the pseudogap near the Fermi level in the icosahedral quasicrystals, although it operates only slightly in the decagonal quasicrystal.