Schedule Nov 18, 2002
Structural Instabilities of the High-Temperature Phases in Metallic Plutonium
Sergej Savrasov, New Jersey Institute
To understand the microscopic mechanism underlying the structural changes in plutonium, simultaneous electronic structure and lattice dynamics calculations are needed.

Here we report these studies by a new computational method based on the dynamical mean field and the linear response theories. This method allows us to incorporate correlation effects between f-electrons, which are important for modeling arbitrary waves of atomic displacements. We compute phonon dispersion relations for the high-temperature phases and find an intrinsic instability of the bcc epsilon-Pu. By estimating the entropy associated with the phonon dynamics in delta and epsilon phases we explain the origin of the delta->epsilon transition as driven by phonon entropy.

The calculated phonon spectra provide an important insight on the vibrations of the Pu lattice.

(**In collaboration with X. Dai, G. Kotliar, A. Migliori, and E. Abrahams)

Audio requires RealPlayer by RealNetworks.
Begin WebCam and audio for the whole talk: high bandwidth or medium bandwidth.
Or, begin audio only for the whole talk: high bandwidth or low bandwidth. (Or, right-click to download the whole audio file.)

Author entry (protected)