Phonons in icosahedral and cubic Al-Li-Cu
- Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States)
- Institut Laue-Langevin, 156X, 38042 Grenoble CEDEX (France)
- Laboratoire Leon Brillouin, Centre d'Etudes Nucleaires Saclay, 91191 Gif-sur-Yvette CEDEX (France)
- Metallurgy Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)
We describe the results of inelastic-neutron-scattering measurements on single grains of icosahedral Al-Li-Cu and the related cubic {ital R} phase. Measurements along the high-symmetry twofold, threefold, and fivefold axes of the icosahedral phase clearly show the existence of well-defined propagating modes, with isotropic dispersion, near strong Bragg peaks. The spectral weight of the acoustic phonons scale linearly with the integrated intensity of the associated zone centers. In several cases we are able to identify quasi''-Brillouin-zones, with stationary points at the special'' high-symmetry points of a simple icosahedral lattice. While the phonon dispersion for transverse and longitudinal acoustic modes along the twofold axis of the cubic {ital R} phase is quite similar to that found for the icosahedral phase, differences are found in the higher-energy modes; the behavior of the higher-energy modes of the icosahedral phase is consistent with an enhanced degree of spatial localization for these excitations.
- DOE Contract Number:
- W-7405-ENG-82
- OSTI ID:
- 7068941
- Journal Information:
- Physical Review, B: Condensed Matter; (United States), Vol. 45:18; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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