Structural origin of resonant diffraction in RuO${}_2$

Abstract

We report Ru L${}_3$-edge resonant X-ray diffraction studies on single crystal and (001) epitaxial films of RuO${}_2$. We investigate the distinct $\mathbf{Q}=(100)$ and $(001)$ reflections as a function of incident energy, azimuthal angle, and temperature. The results show that the observed resonant diffraction in RuO${}_2$ is fully consistent with a resonant charge anisotropy signal of structural origin permitted by the parent (non-magnetic) rutile $P{4}_2/mnm$ space group. These results significantly constrain the magnetic contribution to the resonant diffraction signal and indicate the unlikely existence of $\mathbf{k}=0$ antiferromagnetic order in RuO${}_2$.