Competing charge and magnetic order in the candidate centrosymmetric skyrmion host EuGa2Al2

Abstract

Formula Presented are centrosymmetric systems that have recently been identified as candidates to stabilize topologically nontrivial magnetic phases, such as skyrmion lattices. In this Letter, we present a high-resolution resonant x-ray and neutron scattering study on Formula Presented that provides new details of the complex coupling between the electronic ordering phenomena. Our results unambiguously demonstrate that the system orders to form a spin density wave with moments aligned perpendicular to the direction of the propagation vector below 19.5 K, and upon further cooling below 15 K, a cycloid with moments in the Formula Presented plane, in contrast to what has been reported in the literature. We show that concomitant with the onset of the spin density wave is the suppression of the charge density wave order, indicative of a coupling between the localized Formula Presented electrons and itinerant electron density. Furthermore, we demonstrate that the charge density wave order breaks the fourfold symmetry present in the Formula Presented crystal structure, thus declassifying these systems as square-net magnets.