First Principles Investigations of Plutonium Americium and their

Outline and Conclusion • First Principles Computations of Actinides. • DMFT Results for Plutonium

Computational Approach to a First Principles Description of the Actinides must include • Relativistic

DMFT Phonons in fcc d-Pu C 11 (GPa) C 44 (GPa) C 12 (GPa)

Volume and Spectra alpa->delta volume collapse transition F 0=4, F 2=6. 1 F 0=4.

Americium f 6 -> L=3, S=3, J=0 Mott Transition? "soft" phase f localized "hard"

Am within LDA+DMFT Large multiple effects: F(0)=4. 5 e. V S. Y. Savrasov, K.

Probe for Valence and Multiplet structure: EELS&XAS 5 f 7/2 A plot of the

From J. Shim K. Haule and G. Kotliar to appear in Nature. B=B 0

B=B 0 - 4/15<l. s>/(14 -nf) LDA+DMFT One measured quantity B, two unknowns Close

First results on Compounds, Pu. O 2, Pu-Am mixture, 50%Pu, 50%Am Lattice expands ->

Acknowlegment References-Collaborators • Electronic correlations in metallic Plutonium within dynamical meanfield picture: S. Savrasov,

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First Principles Investigations of Plutonium Americium and their Mixtures using Dynamical Mean Field Theory Gabriel. Kotliar Physics Department and Center for Materials Theory Rutgers University. Funded by : DOE BES and NNSA. Washington February 5 -8 (2007).

Outline and Conclusion • First Principles Computations of Actinides. • DMFT Results for Plutonium and Americium • Preliminary Results for compounds Pu. O 2, Pu. 5 Am. 5. • Mott transition in the actinide series: important science problem. • New theoretical methodologies developed at Universities. DMFT concepts, allow close interaction with experimentalists, key validation and progress.

Computational Approach to a First Principles Description of the Actinides must include • Relativistic Effects, Spin Orbit Coupling • Realistic band structure, complex structures • Atomic Multiplet effects (F 0 F 2 F 4 F 6) • Treat localization –delocalization on the same footing. • LDA+DMFT. Compute total energies from a functional of the photoemission spectra.

DMFT Phonons in fcc d-Pu C 11 (GPa) C 44 (GPa) C 12 (GPa) C'(GPa) Theory 34. 56 33. 03 26. 81 3. 88 Experiment 36. 28 33. 59 26. 73 4. 78 ( Dai, Savrasov, Kotliar, Ledbetter, Migliori, Abrahams, Science, 9 May 2003) (experiments from Wong et. al, Science, 22 August 2003)

Volume and Spectra alpa->delta volume collapse transition F 0=4, F 2=6. 1 F 0=4. 5, F 2=7. 15 Gouder Havela Lander

Americium f 6 -> L=3, S=3, J=0 Mott Transition? "soft" phase f localized "hard" phase f bonding A. Lindbaum, S. Heathman, K. Litfin, and Y. Méresse, Phys. Rev. B 63, 214101 (2001) J. -C. Griveau, J. Rebizant, G. H. Lander, and G. Kotliar Phys. Rev. Lett. 94, 097002 (2005)

Am within LDA+DMFT Large multiple effects: F(0)=4. 5 e. V S. Y. Savrasov, K. Haule, and G. Kotliar Phys. Rev. Lett. 96, 036404 (2006) F(2)=8. 0 e. V F(4)=5. 4 e. V F(6)=4. 0 e. V

Probe for Valence and Multiplet structure: EELS&XAS 5 f 7/2 A plot of the X-ray absorption as a function of energy 5 f 5/2 4 d 5/2 ->5 f 7/2 hv 4 d 3/2 4 d 5/2 Core splitting~50 e. V Excitations from 4 d core to 5 f valence core valence Electron energy loss spectroscopy (EELS) or X-ray absorption spectroscopy (XAS) B=B 0 - 4/15<l. s>/(14 -nf) 4 d 3/2 ->5 f 5/2 Core splitting~50 e. V Energy loss [e. V] Branching ratio B=A 5/2/(A 5/2+A 3/2)

From J. Shim K. Haule and G. Kotliar to appear in Nature. B=B 0 - 4/15<l. s>/(14 -nf) B 0 = (3/5) (for d->f transitions)

B=B 0 - 4/15<l. s>/(14 -nf) LDA+DMFT One measured quantity B, two unknowns Close to atom (IC regime) Itinerancy tends to decrease <l. s> [a] G. Van der Laan et al. , PRL 93, 97401 (2004). [b] G. Kalkowski et al. , PRB 35, 2667 (1987) [c] K. T. Moore et al. , PRB 73, 33109 (2006).

First results on Compounds, Pu. O 2, Pu-Am mixture, 50%Pu, 50%Am Lattice expands -> Kondo collapse is expected charge transfer Pu d phase stabilized by shift to mixed valence nf~5. 2 ->nf~5. 4 Hybridization decreases, but nf increases, Tk does not change significantly!

Acknowlegment References-Collaborators • Electronic correlations in metallic Plutonium within dynamical meanfield picture: S. Savrasov, G. Kotliar, and E. Abrahams, Nature 410, 793 (2001). • Calculated Phonon Spectra of Plutonium at High Temperatures: X. Dai, S. Y. Savrasov, G. Kotliar, A. Migliori, H. Ledbetter, and E. Abrahams, Science 300, 953 -955 (2003). • Many-Body Electronic Structure of Americium metal: Sergej Y. Savrasov, Kristjan Haule, Gabriel Kotliar, Phys. Rev. Lett. 96, 036404 (2006). • J. Shim K. Haule and G. Kotliar , Fluctuating valence in a correlated solid and the anomalous properties of delta-plutonium: to appear in Nature next month. Experimentalists: LANL: A. Migliori, (resonant ultrasound) J. Singleton (magnetotrasnport ) J. Thompson, (EELS X-Ray J. Joyce (Photoemission), J. Lashley (specific heat) Livermore: J. Wong (X Ray scattering) K. Moore J. Tobin (EELS and XAS ) M. Fluss (transport) ITU: . L. Havela J. C. Griveaux and G. Lander (transport under pressure )