Crystallographic chirality of CsCuCl ₃ probed by resonant circularly-polarized hard X-ray diffraction

We have observed the circular-polarization-dependent intensities of forbidden (0,0,6n ± 2) reflections at the Cu K absorption edge in the chiral crystal CsCuCl ₃. The intensities for the right- and left-handed circularly-polarized incident beams interchange in CsCuCl ₃ crystals with opposite chiralities. The result is well explained by a model calculation based on the anisotropic tensor susceptibility of Cu ²⁺ ions, taking only the electric-dipole (E1) process into account. This technique can determine crystallographic chirality by measuring the flipping ratio for only one reflection, in principle.