Investigating Phase Changes n the Sc-II Guest-Structure as Predicted by a Global Neural Network

We will study scandium (Sc) metal up to 200 GPa, resolving long-standing discrepancies in the literature regarding the structure(s) of the incommensurate host-guest Sc-II phase. These investigations are carried out in the context of novel machine-learned material models which have recently predicted that the guest-structure of Sc-II undergoes a transition from face-centred to body-centred tetragonal at 50-70 GPa. We will test this prediction, aiming to either validate this promising new computation technique or provide data which will inform future developments of this approach. In addition, we will attempt to collect high-quality diffraction data to aid in solving the as-yet unknown Sc-III and Sc-IV phases.