title: Phonon dispersions of fcc delta-plutonium-gallium by inelastic x-ray scattering.
abstract: We report an experimental determination of the phonon dispersion curves in a face-centered cubic (fcc) delta-plutonium-0.6 weight % gallium alloy. Several unusual features, including a large elastic anisotropy, a small-shear elastic modulus C', a Kohn-like anomaly in the T1[011] branch, and a pronounced softening of the [111] transverse modes, are found. These features can be related to the phase transitions of plutonium and to strong coupling between the lattice structure and the 5f valence instabilities. Our results also provide a critical test for theoretical treatments of highly correlated 5f electron systems as exemplified by recent dynamical mean field theory calculations for delta-plutonium.
authors.affiliation: Lawrence Livermore National Laboratory, University of California, Post Office Box 808, Livermore, CA 94551, USA. wong10@llnl.gov
authors.forename: Joe
authors.initials: J
authors.lastname: Wong
authors.forename: Michael
authors.initials: M
authors.lastname: Krisch
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Farber
authors.forename: Florent
authors.initials: F
authors.lastname: Occelli
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Schwartz
authors.forename: Tai-C
authors.initials: TC
authors.lastname: Chiang
authors.forename: Mark
authors.initials: M
authors.lastname: Wall
authors.forename: Carl
authors.initials: C
authors.lastname: Boro
authors.forename: Ruqing
authors.initials: R
authors.lastname: Xu