Phys. Rev. Lett. 96, 206402 (2006) [4 pages]Symmetry and Stability of δ Plutonium: The Influence of Electronic StructureReceived 27 September 2005; published 26 May 2006 Using first-principles density-functional theory, we calculate the bond strengths between the 12 nearest neighbors in δ plutonium for both pure Pu and a Pu-3.7 at. % Ga alloy. Our results for pure Pu reveal a structure with the monoclinic space group Cm rather than face-centered cubic Fm3̅ m, showing that the anomalously large anisotropy of δ plutonium is a consequence of greatly varying bond strengths between the 12 nearest neighbors. Further results for a Pu-3.7 at. % Ga alloy show that the nearest-neighbor bond strengths around a Ga atom are more uniform. Hence, our calculations address (i) why the ground state of Pu is monoclinic, (ii) why distortions of the δ phase are viable, with considerable implications for the behavior of the material as it ages due to anisotropic response to self-irradiation, and (iii) why Ga stabilizes face-centered cubic δ-Pu. © 2006 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevLett.96.206402
DOI:
10.1103/PhysRevLett.96.206402
PACS:
71.20.Gj, 71.15.Mb, 71.27.+a, 71.28.+d
See AlsoComment: S. I. Simak and A. V. Ruban, Comment on “Symmetry and Stability of δ Plutonium: The Influence of Electronic Structure”, Phys. Rev. Lett. 99, 019703 (2007). Reply: K. T. Moore, P. Söderlind, A. J. Schwartz, and D. E. Laughlin, Moore et al. Reply:, Phys. Rev. Lett. 99, 019704 (2007). |
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