Analysis of anisotropic compression of uranium under high pressures: a computational and experimental overview

We have investigated anisotropic compression effects observed in uranium metal under high pressures by analyzing data obtained with different X-ray diffraction techniques as well as data on samples obtained with different pressure media. Our analysis shows that the observed anisotropic compression effects are independent of the pressure transmitting medium or the experimental technique employed for studying uranium metal under high pressures. This suggests that the observed anisotropic compression effects are not related to non-hydrostatic stresses in the diamond anvil cell devices. First principle calculations using LMT-Art largely reproduce the experimentally measured axial ratios of the orthorhombic unit cell thereby confirming anisotropic effects in this f-band metal under compression.