In this paper we propose a new pseudo-phase crystal structure, based on an orthorhombic distortion of the diamond structure, for the ground-state α-phase of plutonium. Electronic-structure calculations in the generalized-gradient approximation give approximately the same total energy for the two structures. Interestingly, our new pseudo-phase structure is the same as the Pu γ-phase structure except with very different b/a and c/a ratios. We show how the contraction relative to the γ phase, principally in the z direction, leads to an α-like structure in the [0,1,1] plane. This is an important link between two complex structures of plutonium and opens new possibilities for exploring the very rich phase diagram of Pu through theoretical calculations.
@article{arxiv.cond-mat/0305148,
title = {New Pseudo-Phase Structure for $\alpha$-Pu},
author = {J. Bouchet and R. C. Albers and M. D. Jones and G. Jomard},
journal= {arXiv preprint arXiv:cond-mat/0305148},
year = {2009}
}