Evaluation of first-principles techniques for obtaining materials parameters of α -uranium and the (001) α -uranium surface

First-principles calculations based on the projector augmented-wave (PAW) technique have been applied to the prediction of materials properties of α-uranium and its (001) surface. The results of the PAW calculations are shown to be comparable in accuracy to the full-potential calculations reported elsewhere. In addition to calculating lattice constants and elastic moduli, the vacancy formation energy (1.950.3em0exeV), (001) surface relaxation (-3.5% for δ₁₂ and $+1.2%$ for δ₂₃), (001) surface energy (1.40.3em0exJ∕m²), and (001) work function (3.60.3em0exeV) were also obtained. The overall agreement with experiment is satisfactory. Using an elastic model for brittle-crack failure, a yield stress of 4300.3em0exMPa was estimated. Further exploration of materials failure modes (such as plastic deformation) awaits a larger-scale atomistic treatment. Full spin-orbit and scalar relativistic calculations were shown to give results with similar levels of accuracy compared to experiment.