Calculated phonon spectra of plutonium at high temperatures.
We constructed computer-based simulations of the lattice dynamical properties of plutonium using an electronic structure method, which incorporates correlation effects among the f-shell electrons and calculates phonon spectra at arbitrary wavelengths. Our predicted spectrum for the face-centered cubic delta phase agrees well with experiments in the elastic limit and explains unusually large shear anisotropy of this material. The spectrum of the body-centered cubic phase shows an instability at zero temperature over a broad region of the wave vectors, indicating that this phase is highly anharmonic and can be stabilized at high temperatures by its phonon entropy.
Dai
X
X
Department of Physics and Astronomy and Center for Materials Theory, Rutgers University, Piscataway, NJ08854, USA.
Savrasov
S Y
SY
Kotliar
G
G
Migliori
A
A
Ledbetter
H
H
Abrahams
E
E