Figure 1. (at left) Total energies for the five polymorphic phases of Cm(I-V) as functions of atomic volume for magnetic and non-magnetic calculations. Vertical lines indicate measured transition volumes.

P. Söderlind, J. Klepeis, L. Benedict, A. Landa, R. Hood, A. McMahan, D. Orlikowski, J. Pask, L. Yang, and J. Moriarty

Methods: FP-LMTO, EMTO, MGPT, and DMFT
Collaborators: High-Pressure Physics Group (LLNL), Richard Scalettar (UC Davis), Levente Vitos (KTH, Stockholm)

Predicting the properties of f-electron metals represents a fundamental challenge in condensed matter physics. Their complex geometries, narrow f-bands, and extraordinary heavy nuclei require a highly accurate numerical treatment. Also, correlation effects of the f-electrons impose a special challenge to theoreticians in some regimes. Our goal is the development of accurate multiphase equations of state, phase diagrams, and melt curves for f-electron materials. The primary theoretical tools are temperature-dependent FP-LMTO and EMTO electronic structure calculations, and many-body and angular-force MGPT atomistic simulations, while dynamical mean-field theory is used where correlation effects are particularly significant. Results to date include temperature-dependent FP-LMTO calculations of the equations-of-state, structural stability, elastic moduli, zone-boundary phonons, unrelaxed vacancy formation energies, and ideal shear strengths. DMFT has also been successfully applied to the correlation-driven alpha-to-gamma transition in Ce. We have worked closely with H-Division diamond-anvil-cell experimentalists. This research effort is also closely coupled to the ongoing study of high-pressure strength. In particular, the phase diagram and elastic moduli are crucial inputs for full multi-phase strength models.

Recent Publications

1. K. T. Moore, G. van Lann, R. G. Haire, M. A. Wall, A. J. Schwartz, and P. Söderlind, "Emergence of Strong Exchange Interaction in the actinide series: The driving force for magnetic stabilization in Curium", Phys. Rev. Lett. 98, 236402 (2007)
2. K. T. Moore, P. Söderlind, A. J. Schwartz, and D. E. Laughlin, "Symmetry and Stability of delta Plutonium: The Influence of Electronic Structure," Phys. Rev. Lett. 96, 206402 (2006). Commentary, More commentary
3. P. Söderlind, "Theory of the crystal structures of cerium and the light actinides," Adv. Phys. 47, 959 (1998).
4. K. Held, A. K. McMahan, and R. T. Scalettar, "Cerium Volume Collapse: Results from the Merger of Dynamical Mean-Field Theory and Local Density Approximation," Phys. Rev. Lett. 87, 276404 (2001).
5. P. Söderlind and B. Sadigh, "Density-functional calculations of alpha, beta, gamma, delta, delta', and epsilon plutonium," Phys. Rev. Lett. 92, 185702 (2004).

Maintained by Robert E. Rudd -- Last updated on 9 March 2007.
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