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Physics of f-Electron Materials

P. Söderlind, J. Klepeis, A. Landa, B. Sadigh, F. Zhou, R. Hood, A. McMahan, D. Orlikowski, J. Pask, and Lin Yang and John Moriarty

Methods: FP-LMTO, EMTO, MGPT, DMFT, LAPW and PW.

Collaborators: High-Pressure Physics Group (LLNL), Richard Scalettar (UC Davis), Levente Vitos (KTH, Stockholm), Alexander Lichtenstein (University of Hamburg, Germany)

Elastic constants for plutonium metal
Phase C11 C22 C33 C44 C55 C66 C12 C13 C23 C15 C25 C35 C46
α 120 109 86.2 43.4 50.6 43.7 -9.3 1.1 -11.5 22.1 20.2 21.9 -0.25
β 75.4 64.4 65.1 32.2 22.4 27.2 27.0 20.6 23.1 20.6 21.5 19.4 -0.95
γ 81.0 63.7 70.5 21.6 11.9 21.7 31.5 22.6 22.6        
δ 65.0     38.0     29.0            
δ′ 64.7   62.0 42.1   42.2 43.2 29.6          

Calculated elastic constants for alpha, beta, gamma, delta, and delta' plutonium

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 PW, FP-LMTO, LAPW, 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 CMMD 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. A. Migliori, P. Söderlind, A. Landa, F. J. Freibert, B. Maiorov, B. J. Ramshaw, and J. B. Betts, "Origin of the multiple configurations that drive the response of delta-plutonium's elastic moduli to temperature", Proceedings of the National Academy of Sciences of the U.S.A., 113, 11158 (2016).
  2. P. Söderlind, F. Zhou, A. Landa, and J. E. Klepeis, "Phonon and Magentic Structure in delta-Plutonium from Density-Functional Theory", Sci. Rep. 5, 15958 (2015)
  3. P. Söderlind, P. E. A. Turchi, A. Landa, and V. Lordi, "Ground-state properties of Rear-Earth Metals: and Evaluation of Density-Functional Theory", J. Phys.: Condens. Mat. 26, 416001 (2014).
  4. P. Söderlind and A. Landa, "Theoretical Confirmation of Ga-Stabilized Anti-Ferromagnetism in Plutonium Metal", J. Nucl. Mater. 448, 310 (2014).
  5. A. Landa, P. Söderlind, and P. E. A. Turchi, "Density-functional Study of U-Mo, Np-Mo, Pu-Mo, and Am-Mo Alloys", J. Nucl. Mat 434, 31 (2013).
  6. J. R. Jeffries, P. Söderlind, H. Cynn, A. Landa, W. J. Evans, S.T. Weir, Y. K. Vohra, and G. Lander, "Magnetism and Structural Distortions in Uranium Sulfide Under Pressure", Phys. Rev, B 87, 214104 (2013).
  7. P. Söderlind, K. T. Moore, A. Landa, B. Sadigh, and J. A. Bradley, "Pressure-Induced Changes in the Electronic Structure of Americium Metal", Phys. Rev. B 84, 075138 (2011).
  8. A. Landa, P. Söderlind, and P. E. A. Turchi, "Density-Functional Study of U-Mo and U-Zr Alloys", J. Nucl. Mater. 414, 132 (2011).
  9. E. Gorelov, J. Kolorenc, T. Wehling, H. Hafermann, A. B. Shick, A. N. Rubtsov, A. Landa, A. K. McMahan, V. I. Anisimov, M. I. Katsnelson, and A. I. Lichtenstein, "Importance of Full Coulomb Interactions for Understanding the Electronic Structure of delta-Pu ", Phys. Rev. B 82, 085117 (2010).
  10. P. Söderlind, A. Landa, J.E. Klepeis, Y. Suzuki, and A. Migliori, "Elastic Properties of Pu Metal and Pu-Ga Alloys, ", Phys. Rev. B 81, 224110 (2010).
  11. P. Söderlind and J. E. Klepeis, "First-principles elastic properties of alpha-Pu, ", Phys. Rev. B 79, 104110 (2009).
  12. A. Landa, P. Söderlind, and P.E.A. Turchi, "Density-Functional Study of the U-Zr System, ", J. Alloys Compd. 478, 103 (2009).
  13. P. Söderlind, "Quantifying the importance of orbital over spin correlations in delta-Pu within density-functional theory ," Phys. Rev. B 77, 085101 (2008).
  14. L.H. Yang, R.Q. Hood, J.E. Pask, and J.E. Klepeis, "Large-scale quantum mechanical simulations of high-Z metals," J. Computer-Aided Mater. Des. 14, 337 (2007).
  15. J.-X Zhu, A. K. McMahan, M. D. Jones, T. Durakiewicz, J. J. Joyce, J. M. Wills, and R. C. Albers, "Spectral Properties of delta-Plutonium: Sensitivity to 5f Occupancy, ", Phys Rev. B. 76, 245118 (2007).
  16. A. Landa, P. Söderlind, and L. Vitos, "Density-functional calculations of alpha-Pu-Ga(Al) alloys ," J. Alloys Compd. 444-445 296 (2007)
  17. 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).
  18. 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).
  19. P. Söderlind and A. Landa, "Crystal Stability and Equation of State for Americium: Theory, ", Phys. Rev. B 72 024109 (2005).
  20. A. Landa, P. Söderlind, A. Ruban, L. Vitos, and L. Pourovskii, "First-Principles Phase Diagram of the Ce-Th System, ", Phys. Rev. B 70 224210 (2004).
  21. P. Söderlind and B. Sadigh, "Density-functional calculations of alpha, beta, gamma, delta, delta', and epsilon plutonium ," Phys. Rev. Lett. 92, 185702 (2004).
  22. A. Landa, P. Söderlind, and A. Ruban, "Monte Carlo Simulations of the Stability of delta-Pu," J. Phys.: Condens. Mat. 15, (2003) L371.
  23. P. Söderlind, A. Landa and B. Sadigh, "Density-functional investigation of magnetism in delta-Pu ," Phys. Rev. B 66, 205109 (2002).
  24. P. Söderlind, "Ambient pressure phase diagram of plutonium: a unified theory for alpha-Pu and delta-Pu ," Europhys. Lett. 55, 525 (2001).
  25. P. Söderlind, "Theory of the crystal structures of cerium and the light actinides ," Adv. Phys. 47, 959 (1998).

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