Pressure-tuning topology via charge density waves in Eu(Ga,Al)4

The tetragonal series Eu(Ga,Al)4 hosts complex magnetic and electronic structures throughout: EuAl4 is a novel centrosymmetric skyrmion system, EuAl2Ga2 has an anomalous Hall contribution of unknown origin, and EuGa4 is a nodal-ring Weyl semimetal. The common denominator is a charge density wave (CDW) that reconstructs the Fermi surface and determines an equilibrium of magnetic nesting instabilities. For a global explanation of this electronic-magnetic phase diagram, we propose to characterize the pressure dependence of CDWs in these materials, using high-energy x-ray diffraction from membrane-driven diamond anvil cells. The insights gained in this project may reveal how intermetallic magnetic materials of the ThCr2Si2-type structure have to be designed to stabilize topological properties.