Resonant x-ray diffraction study using circularly polarized x rays on antiferromagneticTbB4

The interference effect between the magnetic scattering and the charge scattering in resonant x-ray diffraction (RXD) leads to circular dichroism. The authors utilize this effect here to distinguish the antiferromagnetic (AFM) domain state in the noncollinear antiferromagnet TbB${}₄$, breaking both the space-inversion (P) and time-reversal (T) symmetries but preserving the combined PT symmetry. This result shows that circularly polarized RXD using the interference effect enables us to detect AFM order parameters and spatially resolve the domain state in PT-symmetric AFM materials.