Structure, formation energies and elastic constants of uranium metal investigated by first principles calculations

The structures, formation energies and elastic constants of α-U, β-U, γ-U, fcc-U, hcp-U and bct-U were investigated by first principles calculations. It turns out that the structures described by the space groups no. 118 and 136 can be identical for the β-U and that the symmetry of β-U should belong to the space group no. 136. Interestingly, it is also shown that β-U might exhibit some isotropic behaviors and that both γ-U and fcc-U are unstable in the ground state because their Zener's shear constants are negative. The results and conclusion obtained in present study are supported by or consistent with others theoretical prediction and experimental observations.

► Structures, formation energies and elastic constants of uranium metals were obtained.
► The structures described by the No. 118 and No. 136 can be identical for β-U.
► Both γ-U and fcc-U are unstable in the ground state.
► β-U might exhibit some isotropic behaviors.