Magnetic Excitations in Chiral-Structure Phase of Ce3Ir4Sn13

In this study, we investigated the electronic states of Ce3Ir4Sn13 by neutron and X-ray scattering. Crystal structure refinement analyses based on synchrotron X-ray diffraction revealed chiral symmetry with space group I213. The highenergy inelastic neutron scattering spectra indicate two crystal-electric-field level schemes of Ce3+ ions, which are attributed to the inequivalent Wyckoff sites in the chiral structure. The spectrum widths indicate that one of the Ce3+ 4felectron states is hybridized with conduction electrons, which is consistent with the Kondo semimetal feature, while the other state is well-localized. The low-energy spectrum reveals spin fluctuations at approximately 0.1 meV, which emerges below 10 K and far above the weak antiferromagnetic ordering temperature of 0.6 K. Moreover, considering also the large absolute value of the Weiss temperature of -33.1 K, we propose an additional magnetic frustration effect.