Strength and Structure of Ce up to 300GPa

Cerium (Ce) is the most abundant of the rare-earth metals and is of great interest to the high-pressure community due to its unique behavior under pressure; it has a very complex phase diagram, including an isostructural volume collapse unique to the lanthanides and attributed to two minima in its interatomic potential. Above 13 GPa, Ce stabilizes in a body-centered tetragonal (bct, tI2) phase. Using bevelled and toroidal DACs, we have statically compressed Ce to multi-megabar conditions and observe changes in the axial ratio and abnormal compressive behavior. We explore the effect of shear stress on these samples and present computational results in support of the experimental data.