High-Pressure Investigations of Crystal Structure and Magnetism in EuZn2As2

The Zintl phases found in some intermetallic compounds have stimulated extensive interests due to their unique thermal and electronic properties, having relevance in the electronics, automotive, and aerospace sectors. EuZn2As2 is a particularly interesting Zintl compound in which the interplay between its isotropic hole band and its unique topological behavior provides a niche landscape for probing the quantum phenomena. This study attempts to understand the structural and magnetic transitions of EuZn2As2 under high-pressure conditions up to 57 GPa. Our synchrotron X-ray diffraction (XRD) data shows a pronounced diffraction peak splitting, indicating a structural transition near 36 GPa. Additionally, a pronounced trend was observed in the magnetic ordering temperature which increased continuously from an initial ~20 K at ambient pressure to a value exceeding 200 K at 30 GPa. Furthermore, our X-ray absorption spectroscopy (XAS) at the europium L3 edge revealed changes of the divalent Eu2+ state towards trivalent Eu3+ beginning around 30 GPa. The significant escalation in the magnetic ordering temperature, crystal structural transition and concomitant valence change prove the material an exceptional candidate for exploring the interplay between quantum phenomena under pressure.