Investigated with Resonant Soft X-ray Scattering*

The axion insulator, a novel topological phase, is predicted to have a topological magnetoelectric effect and axion quasiparticle. However, few stoichiometric examples of the axion insulator have been discovered. Recent work has proposed EuIn₂As₂ as an axion insulator candidate, where the magnetic order of the Eu sublattice may impact the topology of the system [1]. In order to understand the topological properties of EuIn₂As₂, it is therefore crucial to understand its magnetic ordering behavior. Neutron [2] and resonant hard X-ray studies [3] have indicated that the system has a helical-type magnetic order with symmetry that can maintain this topological phase. However, our recent work in resonant soft X-ray scattering (RSXS) paints a different picture. In this talk, I will present temperature-, energy-, and azimuthal-dependent RSXS studies on EuIn₂As₂, which add a further layer of complexity in understanding the magnetic order in this fascinating system.

[1] Xu et al. (2019) https://doi.org/10.1103/PhysRevLett.122.256402

[2] Riberolles et al. (2021) https://doi.org/10.1038/s41467-021-21154-y

[3] Soh et al. (2023) https://doi.org/10.1038/s41467-023-39138-5