Impacts of pressure to the structural, electronic and magnetic properties of Dirac semimetal EuMnBi₂

We report our investigations on the effects of pressure on the electronic and magnetic properties of magnetic Dirac semimetal by using electrical transport, synchrotron x-ray diffraction, and x-ray absorption spectroscopy. The antiferromagnetic interaction due to the Eu magnetic moment in is enhanced under pressure up to . The Néel temperature () is found to disappear above 4 GPa and a new transition at around 29 K emerges above 6 GPa. remains relatively constant up to 15 GPa, above which it increases with further compression, reaching at 22 GPa. Eu -edge x-ray absorption spectroscopy revealed a valence change of Eu toward a trivalent state that begins above 6 GPa, which indicates that is likely related to the valence transition temperature of Eu. Sign reversal of the Hall resistivity above 7 GPa suggests that the valence change of Eu also induces a Fermi surface modification.