High-pressure behaviour of Zintl-type europium compounds with unconventional magnetic and topological states

We propose to study the magnetism and valence states of europium in the Zintl-type compounds EuMn2P2 and EuCuAs at high pressures up to 30 GPa by temperature and field-dependent 151Eu nuclear forward scattering at beamline ID 14 and the pressure dependence of their room temperature crystal structures at beamline ID15B up to 40 GPa. EuMn2P2 is a magnetic insulator with two magnetic elements. Surprisingly, the Mn sublattice does not develop long-range magnetic order. High-pressure transport studies indicate a transition to a metallic state above 5 GPa. In EuCuAs, the topological electronic states and properties could be tuned via the Eu spin structure, which is sensitive to magnetic fields. The proposed high-pressure synchrotron experiments, together with transport studies and electronic structure calculations, will allow us to elucidate the interplay between the covalent M-X and the ionic Eu sublattices in magnetic and topological Zintl-type europium compounds of recent interest.