Structural evolution of f-electron systems under dynamic compression*

Rare earth, 4f elements play a key role in modern day technological applications, such as computer memories and permanent magnets. Additionally, rare-earth superhydrides have recently been discovered to have near room temperature T_c for superconductors above Mbar pressures. As such, understanding and predicting the material behavior of lanthanides is crucial. This can be done using equation of state information, however, f-electron lanthanides impose a unique challenge in performing first-principles calculations due to their complex electronic and lattice structures. Therefore, experimental equation of state measurements are paramount in providing benchmark data to tightly constrain the ab initio calculations. Here, we present direct evidence of phase transitions and melting along the principle Hugoniot in several lanthanide members using in-situ laser shock diffraction at the Dynamic Compression Sector.